6L80 Tear Down and Inspection - Three Clutch Packs Smoked

Added: 2026-05-14

[00:00:02]Hello there. Welcome. Thank you so much for tuning in. Uh today we have a 6LE on the bench out of a 2008 Cadillac Escalade all-wheel drive. And situation here is that this thing has no reverse, shuttering at low speeds, as well as slipping in forward gears. So all the usual symptoms that these these things come in with. And I'm venturing to guess that the uh causes are combination of torque converter, pressure regulator valve wear, and possibly leaking 35R drum. um and maybe even a a partially cracked 1 2 3 4 piston. Uh these early units are plagued with design issues and pattern failures that GM corrected over the years primarily starting in 2009 when they did away with the traditional uh ceiling ring design on the Palm Stator shaft and went to a locking style uh ceiling ring with a support O-ring underneath. So anyway, take a quick look around the case. You'll see that one of the bolts here is not all the way in.

[00:01:01]Not sure why that would be.

[00:01:05]Spin it around here. Most of these things will come in with anywhere between, I would say, 20 and 40,000 of front end play. I like to reduce the end play down to at least, or I should say at most, 10,000 of an inch using the Superior Tech um shim and spacer kit.

[00:01:24]This feels about like 25,000.

[00:01:27]if I had to venture a guess. All right.

[00:01:30]Check your splines, too. It's a good opportunity to just give them a preliminarily um preliminary glance. And then you have your torque converter O-ring. If this O-ring gets hard, you'll have converter clutch issues. P0741.

[00:01:45]And this one seems to be pretty hardened.

[00:01:49]Yeah, look at that.

[00:01:52]So, we have a hardened O-ring.

[00:01:55]Right away we noticed a potential cause for converter shutter which was happening. And these torque converters they are um designed to come on in second gear through sixth gear. And a lot of folks will tune that out and have the torque converter lock up only in fifth and sixth gear. So 15 mm on our um shift shift linkage bolt or nut rather.

[00:02:32]And then extension housing is also 15 mm.

[00:03:16]I think that method will be by hand.

[00:03:24]All right, not much to say about the back of the case other than the fact that the four-wheel drive units will have a seal and the two wheel drive units will not. So, if you're working on a two wheel drive 6L80 or 90, do not install a rear seal um where it would normally go for the 4x4 units. You'll see in a second once I get this last bolt off.

[00:03:45]All right.

[00:04:03]Looks like we don't have a rear seal here at all. This should be a machine cut square seal in this location. So, I wonder if that thing was off at some point.

[00:04:16]for some reason. Possibly to take the unit out of the vehicle. I don't know.

[00:04:22]All right. So, pump the case bolts are going to be 15 mm. In fact, you know what? I'm going to actually flip this thing over. We'll get pan and valve body off.

[00:04:34]Let the fluid drain and then we'll go ahead and remove the belt.

[00:04:41]So 10 mm on all these bolts, 80 inbs.

[00:04:46]Then you go back to reinstall.

[00:04:56]A reusable pan gasket will come in your overhaul kit, so you don't want to reuse this one.

[00:05:04]Though, if you're going to paint the case, clean the gasket off and use it as a masking aid, you know, in combination with the pan so you don't get overspray, you know, into the interior of the unit.

[00:05:19]Fluid stinks real bad.

[00:05:22]Definitely burn up.

[00:05:25]One or more clutch packs fried, I would guess. Got one more bolt. And two more.

[00:05:45]Oh yeah. Nasty, nasty, nasty.

[00:05:57]All right. All right. If you're doing a service, it's a good idea to cut the filter open, especially if you're having some kind of, you know, strange uh drivability symptoms, shifting issues, and you just want to cut it crossways on a band saw or something so that you can see what might be trapped inside of it.

[00:06:13]You know, things like metal debris, you know, we see a lot of glittery looking material, which is burn clutch material, uh, whether from inside the case and or the torque converter clutch. A lot of silvery sandlike material will be indicative of torque converter failure.

[00:06:29]So all things to be on the lookout for when you're doing a service. You know, it's always a good idea to try and spot those things straight away.

[00:06:49]All right. Let that drain into the catch container.

[00:07:02]All right. Lift up on your gate latch.

[00:07:03]That will allow you to free the entire control body assembly from your case connector here.

[00:07:13]All right. 8 mm on your detent roller bolt.

[00:07:21]And then you have six what I will refer to as starfish bolts holding the entire control body assembly to the case. You don't have to disconnect any, you know, anything you see on here in terms of electrical connections. This whole assembly just comes right off once you remove these starfish bolts.

[00:07:49]All right. So, the socket I'm using is Snap-On 10 EPL All right. 2006 through 2013, all these valve bodies came with seven check balls from the factory. Starting in 2014, they added an eighth check ball.

[00:08:27]You can retro the uh eighth check board back to 2010 as long as you're using the uh third design spacer plate that is designed to accept that configuration.

[00:08:57]All right, we'll deal with the valve body later.

[00:09:02]I mean, there is just a ton of burnt clutch material here.

[00:09:08]All right, now you'll have seals on the back of it going to these apply circuit locations here. And then you have your 26 and reverse circuit location seal in this position. Okay, they also come in your overhaul kit.

[00:09:25]All right. Uh, for your shift linkage, you're going to need roll pin pullers.

[00:09:30]Uh, it's a factory pilot style puller.

[00:09:33]It allows you to knock the roll pins out via a slide hammer. And so if you don't have that, this one and this one, which you can knock out with a pin punch, and this one with diagonal cutters, usually um you know that that's the uh the normal way to go about removing them. This one on the other hand, you will absolutely need the tool for. So, if you don't have the tool or it's so expensive that it's just, you know, you can't afford to buy it or it's just not worth it for you, then scrutinize this area here. Make sure that these O-rings that are on your parking pole housing are not leaking. Cuz if they're not leaking, then you really don't have to take this off. You can take the entire transmission fully apart, evacuate the whole case without ever having to remove this.

[00:10:24]All right.

[00:10:30]punch the inspection covers out.

[00:10:36]Let me see if I can get this thing up on the stand. We can take the bell off.

[00:10:58]All right. Anytime you're working on a 2008 unit and older, you want to always install a 2009 and up stator into uh you know the pump assembly because it will have a locking style ceiling rings and support O-rings which GM introduced to eliminate the tendency for those circuits to cross leak due to the traditional ceiling ring style design not sealing effectively against the interior of the 35R drone.

[00:11:48]All right. And there is a snap ring here that more or less holds the front seal in place. So, we'll we'll get that out of there.

[00:12:37]All right, let's go ahead and disassemble the pump.

[00:12:45]8 mm on all the pump half bolts. So stator support to bell.

[00:13:17]All right. There is a tightening and torquing sequence for these bolts. So, when you're reassembling the unit and you're going back with the pump specifically, you need to follow that torque sequence. It's in the ATSG manual. And if I have it handy, I'll flash it across the screen so that you can pause the screen, take a screenshot or otherwise refer to it.

[00:13:43]All right. So again, like I say in all my videos, you're not going to really do any serious inspections until the case has been cleaned up, all the parts through your whatever cleaning cycle you have so that you can see everything clearly. But you obviously want to inspect your working surfaces. Um, I actually can't remember the last time I had one of these in where we were able to use both the stator half and the body as is where there was no machine work required. Um, come to think of it, I don't believe that I ever had such a case with one of these transmissions.

[00:14:20]All right, so here is your pressure regulator valve. So, this is the um valve that lies at the root cause of so many problems with these transmissions.

[00:14:30]And from what I've seen, they're worse with the earlier units.

[00:14:35]And yeah, that definitely makes sense, right? the earlier your units will have the more miles, but it seems like it's, you know, mileage taken into account.

[00:14:42]Um, there seems to be something else at work there as well. So, just push in the boost valve sleeve so that you can allow the roll pin to come out. That holds everything in.

[00:14:57]And then you can just start taking out your components. So, you're going to have a bumper spring and a pressure regulator valve spring.

[00:15:12]So, the most popular thing to do here is to install the Sonic's second design drop in pressure regulator valve from their zip kit. And it's sold individually in addition to being part of that kit.

[00:15:28]But a lot of times this valve will be so worn and you're starting to see some of the wear here on this one. right here on the balance spool. It'll be so wore out that the recommended course of action at that point is to do, you know, bypass the drop in valve and just ream this bore out for an oversized valve if you're going to reuse the stator support half.

[00:15:55]All right. No reason to take the rest of it apart.

[00:16:01]Just wanted to look at that valve. So, these bushings, always replace them. I replace all the bushings in these transmissions. Um, you're going to have your thrust washer here. When you machine the stator support and the body/bell, you're taking 20,000 of an inch off. So, 10,000 off the stator half, 10, you know, stator support half, I should say, and 10,000 of an inch off of the body.

[00:16:26]So, what that requires is an oversized thrust washer here for the stator. And Sonic sells those. So you want to install that cuz that will preserve the inflat between the pump and the 35 in reverse drum.

[00:16:44]And I'm trying to get this off so I don't break it because I like to have these as spares in the event I need them for some reason.

[00:16:52]There we go. So you're just going to push inward on these locking tabs.

[00:16:59]All right. If you're going to reuse a stator shaft, say for an 09 and up, you want to check the splines, check the inner diameter for ring cut for the input shaft, ceiling rings, check here on this journal, make sure that it's okay. You know, nothing marred up about it or what have you. And of course, you know, um, look over the casting. And then you're going to need to take your alignment dow out before it goes to the machine shop. This one's just going to get cleaned up, but we're not going to do anything else with it. If I could find an individual stator shaft and that stator support is otherwise good, you know, the other valve trains, um, I'll just install a new stator shaft for the new gasket.

[00:17:39]All right, let's check our body, our gears, or gears, rotor, and slide.

[00:17:48]Okay, now factory rotor and slides are pretty resilient. So, unless yours is broken or otherwise damaged, you could reuse it. You just want to check here for the engagement losses on the torque converter. Make sure that there's no cracks and make sure there's no cracks anywhere else on the rotor itself.

[00:18:07]And then for the slide, you're going to kind of more or less do the same thing.

[00:18:11]You're just going to check for condition on the interior. If you're going to replace the rotor and the slide, it is my strong recommendation that you use OEM parts. I would not use aftermarket All right, you're going to put all your veins in a new rotor guide. To my knowledge, this unit has never been overhauled. Customer has no record of it either. Um, I don't know off hand how long he has owned this this vehicle, but as far as he knows, it's never been touched.

[00:18:49]Now, here's your pivot pin and spring.

[00:18:52]Unlike the 4L60 E700R4s, the spring is integral to the pin. Doesn't come off of it. New overhaul kits will have a slide support and a slide support O-ring.

[00:19:04]Almost dropped that.

[00:19:08]And I had it out and now it won't come back out.

[00:19:12]It was dangling there and then I stupidly allowed it to go back into its groove.

[00:19:21]There we go. So, there's the slide support itself. It's teflon.

[00:19:27]And the slide support O-ring is very similar. is very similar in terms of overall diameter and appearance to the base O-ring in the 35R clutch drum. But do not get them mixed up because if you do, you'll have problems. They're not interchangeable.

[00:19:54]All right, the rest of these can go in the trash.

[00:20:00]I took a gander at the working surface.

[00:20:03]I mean, it's got all kind of scoring.

[00:20:05]You know, there's all manner of clutch material in that bushing. You're obviously going to replace this bushing and your seal during overhaul.

[00:20:21]All right, got your 35R clutch drum and your 456 drum along with your intermediate shaft. And I can see right away the 456 clutch is smoked.

[00:20:39]I mean, this is absolutely char broiled.

[00:20:42]I mean, this bearing right here is probably not trustworthy.

[00:20:45]just replace it. Easy deal.

[00:20:51]So, this is going to be your 456 damper.

[00:20:56]It's got a wave snap ring and this is the side that faces inboard.

[00:21:10]So, check the surface here. This is actually friction material as is this.

[00:21:14]Um, if you're installing the SonX 456 high cap uh piston kit, they have you modify this part of the damper by removing, I think, four segments of friction material from it. Stick this here for now.

[00:21:38]All right. Check these splines. Make sure that they're not wore out, winnowed, or otherwise damaged. Same with your um hub lugs. You have a bearing here. Notice that the tabs on it will face up or face you.

[00:21:58]All right, let's see what else we're working with here.

[00:22:03]Check that planet and some gear in a second.

[00:22:07]So, here's a four tab washer. goes on the planet. And then you have a bearing right here.

[00:22:15]Okay, he's going to get a bearing kit.

[00:22:17]There's no way I'm reusing these bearings.

[00:22:20]Check your ring gear. And then what we're going to do is put some transmission fluid right in here because sometimes these spin wheels will break.

[00:22:27]They'll be porous and they'll leak.

[00:22:29]Especially if you see the 456 clutch smoked like that. You always want to check to do a pressure test. So, if you're familiar with 700 R4s for all 60 ES and the input drums there, it's the same principle. You want to see if there's any leaks here at the base of where um the drum is welded to the in the input shaft.

[00:22:53]And these spin welds are vulnerable in these and the Ford six-speed equivalents. So, you know, it's something you always want to check.

[00:23:15]All right, we'll go ahead and put air.

[00:23:17]There's a dual feed system in these these input shafts. So, you have a feed hole here. Plug it with a finger and then put a little bit of air in the other feed.

[00:23:29]You don't need a ton of air. I'm using about maybe 30 40 PSI.

[00:23:36]You want to do this a few times.

[00:23:53]All right. I don't see any leaks. So, that is not the uh cause of the, you know, cook off, if you will. I'm going to check the ceiling rings, too. Just eyeball them.

[00:24:18]Look for any areas where they're flat or otherwise lacerated. you know, anything that would lead you to uh lead you to a direct cause of the failure of this clutch pack. And that's going to be, you know, universally true in terms of your approach. You want to find direct causes of failures. All right, we're going to test a 25R drum as well.

[00:24:42]So, let me get some of this fluid out of the way.

[00:24:55]smoked.

[00:25:00]All right. The 456 clutch, the 1 2 3 4 clutch, and the 35R clutch all have selective snap rings for the clutch.

[00:25:07]So, if you build these a lot, you want to kind of stockpile snap rings whenever you can.

[00:25:13]Is it roasted?

[00:25:16]absolutely roasted.

[00:25:24]I'm just going to take them out two or three at a time. I mean, they are right on the edge of being welded together, which if that happened, then he'd have, you know, forward movement. And maybe he did have that. These two are welded. So, you know, two frictions and a steel down there. And that that would explain the shuttering at low speeds because he would have tie-ups. This clutch is not obviously supposed to be on in low speeds.

[00:25:52]So, he's going to need a whole new probably going to need a whole new drum.

[00:25:58]I don't know if I'm comfortable using this drum. Drum cushion plate backing plate.

[00:26:05]And this is all no good.

[00:26:09]All right. I'm going to take the piston out. see if we can learn anything by inspecting the ceiling surfaces on that piston. You know, either the apply or the balance piston.

[00:26:24]May even replace the snap ring as well for the piston set.

[00:26:40]Crispy critters.

[00:26:53]All right. Note the orientation of the return plate. Got the teeth facing up.

[00:26:58]Facing you.

[00:27:20]Yeah, this this piston feels fairly supple all the way around both the perimeter and the interior lip seal.

[00:27:29]Let's check the balance piston because if either one of these is no good, hardened or what have you, you'll have a smoked 456.

[00:27:37]Um, the other thing that could explain it is restrictions in the system developing as another clutch pack like say the 35R clutch or 1234 clutch burned and you know one thing leads to another and you have um you have flow issues that prevent adequate cooling and the 456 is the most vulnerable clutch when it comes to overheating in these units just you know by nature of the design.

[00:28:08]All right, these snap rings are heat treated from the factory. They're pretty robust and designed to last through even multiple um overheating cycles where, you know, you might see something like this powdered metal backing plate fail or fracture if you were to put it back in after something like this. So, that's why we would never do that.

[00:28:31]All right. probably going to replace that um return plate as well. Like pretty much everything out of this drum and the drum I'm going to suggest we replace because I'm not comfortable using it when it has sustained this much heat soaking. I mean, you guys can tell me different. Maybe you have and you've not had issues with them coming back or having repeat failures, but you know, I'm generally more conservative and uh stricter when it comes to uh suitability for reuse on parts like that.

[00:29:04]All right, we're now going to test the 35R drum for leakage.

[00:29:08]Um up to about 2012, I would say these drums love to leak here at the base welds. The wells themselves were flimsy.

[00:29:17]You know, they love to leak and that would smoke the 1234 I'm sorry, the 35R clutch. 1 2 3 4 clutch would fail because the piston would crack or you'd have cross leaks between the stator and the inner diameter of this drum.

[00:29:40]Now you make sure that's all the way down. I'm going to put a little fluid here.

[00:29:46]Let's go all the way around the welds with the fluid. And we're going to look for bubbles.

[00:29:54]So, we see bubbles. We know that this drum has to be welded up. And I weld up all of them, but it would allow us to explain say a burnt 35R clutch.

[00:30:07]Okay. Again, same amount of uh air. You don't need a ton of it.

[00:30:11]So, 30 to 50 PSI.

[00:30:22]Is that our airble bleed hole? I think it is. Yes, this is our air bleed hole.

[00:30:26]So, you will see bubbles and whatnot coming out of there.

[00:30:33]You know what I didn't do?

[00:30:35]I didn't attach my locking plate.

[00:30:48]I can see that 1 2 3 4 clutch is smoked.

[00:30:51]So, I'm curious to see what that piston looks like.

[00:30:59]All right, let's do it again.

[00:31:04]And no leaks here.

[00:31:25]Okay. Charging the circuit with about 30 to 50 PSI.

[00:31:30]So this drum actually doesn't leak.

[00:31:41]So a lot of heat sustained on the vacuum plate here and that's due to the 456 clutch burnt. That's you know adjacent heating if you will heating up of another part that's burned and then had residual or collateral effects on this part. So there's a relatively thin snap ring.

[00:32:03]Okay. So we have definite signs of overheating on this clutch.

[00:32:09]Scoring.

[00:32:12]No overt slipping though.

[00:32:16]Backing plate looks okay. At least um the underside of it. the clutch facing side.

[00:32:31]All right, this is our 35R apply ring.

[00:32:33]Sonics makes a high cap 35R apply ring that deletes the cushion plate.

[00:32:39]Um, they also make the 456 piston kit.

[00:32:42]And with that kit, if you install it, you add that extra friction and steel, you're going to delete your cushion plate. And as a result, you will need to turn off the airbleleed in the 456 shift table. If you don't do that, then you might have problems. You know, the either tie-ups or erratic shifting. The other thing I'll point out is you notice there's blind splines here.

[00:33:11]So, this is the blind spline for the 35R clutch or blind lug. You want to make sure that you're snap ring in straddle that so that you don't have issues with the snap ring popping out.

[00:33:25]And then same with the 1 2 3 4 clutch.

[00:33:33]And here's our 1 2 3 4 snap ring. This is our 35R snap ring.

[00:33:40]See what we got here.

[00:33:48]And this would explain the shuttering at low speeds that he was uh referring to.

[00:33:57]Absolutely char boiled.

[00:34:04]All right, there's your cushion plate.

[00:34:10]Obvious signs of slippage here. All right. You're going to have your snap rings for the um the piston and return plate assemblies.

[00:34:32]Strongly recommend that you go back with a new set of snap rings. You have two of them there that you're going to replace.

[00:34:40]And that's especially true if your 6L comes in looking like this.

[00:34:48]These clutch packs, you know, if they are smoked, burnt smitherines, I mean, that's going to fatigue the metal in those snap rings, and they're vulnerable to failure anyway.

[00:35:19]All right, let's see what we got here.

[00:35:21]So, here is our piston. This is our applied piston here in my right hand. We have our return plate. Again, the teeth are facing up.

[00:35:30]And then we have our balance piston.

[00:35:38]I'm looking for any cracking, any breakage.

[00:35:47]So, if you notice here, laser engraved in the piston and many other parts of these transmissions is going to be the u um data production. So, this way you can quote unquote date your parts to know which parts you have and what you're working with. could also be able to tell whether or not a a transmission has been overhauled in the past.

[00:36:07]All right, this piston actually looks okay.

[00:36:12]Let's check the balance piston.

[00:36:23]This area right here, this feels different than the rest of it.

[00:36:30]It's like it's flattened or something.

[00:36:33]And that by itself will be enough to explain his issues. Um, and why this clutch burned up the way it did. All right, we have another snap ring that has to come out.

[00:36:48]See way down there. That's your 35R applying balance piston snap ring. And you have an O-ring right here that serves as the boundary between your 1234 and your 35R clutch. In fact, let's take that out. Look at it real quick.

[00:37:06]It's actually not an O-ring. It's a a D-ring.

[00:37:21]Yeah, it's starting to harden a little bit. Not much. I mean, it's not like rock hard. It's still supple, but you can start to feel it just a little bit, you know, at certain sections.

[00:37:35]So, when you're installing um these pistons here, I'm talking about the 35R.

[00:37:40]Do not install this O-ring prior to doing so. Otherwise, you risk cutting the O-ring, especially if you're not perfect with your snap ring, and you know, it somehow allows everything to push forward. It might lacerate the O-ring. All right, I'm going to take that snap ring out and then we'll look at the 35R set.

[00:38:10]I don't have to actually bring my tool back over here so I could force these pistons out because there's no way I'm going to get them out by hand.

[00:38:56]Let's bring them on in all the way.

[00:39:40]Heat. Heat.

[00:40:13]All right. Don't worry about bending this up a little bit. Like I said, you're going to replace it anyway. You just want to be careful when you reinstall the new one so that you don't, you know, contort it and fatigue it. All right. A lot of clutch material has worn away the ceiling surface down here at this location.

[00:40:55]And that's this is the apply piston.

[00:40:57]Here's the balance piston. And then of course you have your return plate.

[00:41:02]Again, teeth facing up.

[00:41:04]So you got three seals here. One, two, three. You got one here. And then there's two more in the drum. And this seal that I'm taking out now is what can be confused for your uh slide support seal or O-ring inadvertently and you may end up putting, you know, the wrong seal in the wrong location. So just be mindful of that. If it would be helpful, just keep your seals, you know, together so that you don't make that mistake and then you can compare them. I mean, a lot of times it's just easier to keep them on the drum. All right. You got one more down here.

[00:41:45]Okay. And like I said, it's I sometimes, even though I've done plenty of these, I'll still get confused about which groove is for the seal, which groove is for the snap ring. So, I'll just leave that one in.

[00:42:01]All right. And the ATSG manual has a diagram that can tell you exactly what goes where.

[00:42:12]All right, last thing I'll remark about is the captured needle bearing assembly here. A new one will come in your overhaul kit, so it's a good idea to replace it, especially if the drum sustained a lot of heat.

[00:42:24]All right, so that drum is going to be taken to the machinist. You want to be well reinforced. He'll check it over as well. Make sure it's okay. You know, there's not some kind of major issue with it that I didn't see or didn't catch.

[00:42:38]And then if you want to keep track of your snap rings, just put them back where they went in here. It's not a huge deal to pay attention to the line lug. I'm just putting them in here. They're not going to go anywhere when I put this in the hot tank.

[00:42:57]All right.

[00:42:59]So, inspect your pistons as well. These are a hard part. They're not normally replaced during the soft part overhaul.

[00:43:07]They look okay, but I'll scrutinize them a lot more carefully once they're clean. All right, let's take a look at our front planet and sungeear. All right, sungeear is orientation agnostic. You can put it in any which way. It doesn't matter. All right, make sure none of the teeth are chipped or, you know, cracked. Make sure the gear is in healthy, good shape.

[00:43:29]Okay, here's your four tab washer. Looks similar to the two tab stator washer.

[00:43:33]So, don't get those mixed up.

[00:43:36]All right. You'll notice there's indexing grooves here on each of the pinion gears.

[00:43:41]So, you just want to check them for side play.

[00:43:44]Check them for vertical play. If you're doing something performance with a 6L80, a 6L90 front planet will just drop right in. They're six pinion. a little bit stronger, a little bit more robust.

[00:43:56]Check your splines here. Check structure. Make sure you don't see any bluing here on the planet itself. If you see bluing on the pinions, I would not reuse this planet. This particular one appears to be okay.

[00:44:10]All right, let's turn our attention to the rest of the case.

[00:44:21]So, we got our hubs in there. 35R 1 2 3 4. So, here's our 1 2 3 4 hub. This bearing is a good idea to replace it.

[00:44:30]So, like I said, we're going to be putting in a bearing kit in this thing.

[00:44:33]So, it'll get all new bearings.

[00:44:37]Check your splines. Check your lugs for lug wear. We see a lot of heat soaking on this one.

[00:44:44]You know, check around here at the base.

[00:44:47]I've never seen one of these actually broke in there, but I guess anything is possible.

[00:44:54]All right. So, that's your 1 2 3 4 hub.

[00:44:56]Here's your 25R hub.

[00:45:01]All right. You have bearings. So, this bearing goes in board on the hub. And then you have another bearing that goes to the center support. Notice it has a locating flange. Now, if you locate it so you know which way it goes back.

[00:45:18]All right. This one is the same. and it's got a locating flange and allows you to locate. Now, note that this bushing, which has to be replaced, notice it's seated at a depth that allows the locating part of the bearing to drop in without interference.

[00:45:38]All right. Check splines, check hose, look for chattering.

[00:45:45]I don't see any. Nothing obvious anyway.

[00:45:49]All right. Right now, we need to get out that snap ring for the center support.

[00:45:52]It's big and beefy. So, we have our snap ring pliers. So, just a couple things.

[00:45:56]First, um have some eye protection on.

[00:45:59]If you have a whole bunch of fluid still in the case, this thing slips off the tongues. It's going to splash fluid back in your face, and you don't want that get into your eye. All right. The next thing is I would tap on the snap ring here at the uh kind of slot in the case where it sits. You're not trying to get the snap ring out of the groove.

[00:46:20]That's going to be very difficult to do.

[00:46:22]But what you are trying to do is loosen it up a little bit to kind of break the bond or the tension that it has so it doesn't stay stuck in the when you're trying to remove it using the pliers.

[00:46:37]All right. And you can tap on it elsewhere too if you want to free it up or at least, you know, relieve tension.

[00:46:54]This helps a little bit. I'm not going to lie to you. It's not a huge difference maker, but you know, every little bit helps when dealing with this thing. So, I got to orient it toward me and then try to get it so that the two ends are kind of toward the bottom at like roughly the 6:00 position.

[00:47:18]There we go. Cuz it makes it easier to grab on the snap ring.

[00:47:41]There we go.

[00:47:46]You know, I said earlier that I don't think this thing's been rebuilt before, but I noticed something right here in the case. You know, like a scratch mark or something. I don't know. that the factory, but this thing can be a real pain in the ass. All right, let's go ahead and get this thing out.

[00:48:15]This is another thing that can give you trouble, too. It'll get caught sideways in the case like it just did here. If so, just tap back on it.

[00:48:37]Get that bearing out of the way.

[00:49:02]All right. So, here's the support.

[00:49:10]The 26 clutch and the low reverse clutch are said to have 50,000 clearance according to the ATSG manual. However, I've seen numerous clutches um or I should say numerous Q6 and uh low reverse clutches come in where they had a lot more clearance than that. Though this looks like it has about 50.

[00:49:30]Now, let's take a look.

[00:49:34]Okay, 26 clutch appears to be fine.

[00:49:42]Look at the backing plate.

[00:49:46]Looks in good shape.

[00:49:48]to each of our frictions and seals. I don't see any signs of slip marks or anything like that.

[00:50:00]All right. All new frictions and steels throughout the transmission. You know, you don't want to be reusing that stuff.

[00:50:05]Don't reuse steels unless you absolutely positively have to. All right. Here is the snap ring for the drone itself.

[00:50:15]or I should say the return piston, you know, return plate.

[00:50:19]Return piston.

[00:50:22]All right. Very easy to get out, but it's also very sharp, so be very careful.

[00:50:34]And I just kind of work it all the way around and it'll come out. And then I show you a trick for getting this thing back in. It works if you're working on a nonuni gear case. So, in other words, where the the rear ring gear output shaft assembly has snap rings, you can use that as a tool to start this thing into its groove and then use a hammer to finish it off.

[00:51:06]There's burn clutch material everywhere on this plate. All right. This is um I believe the only plate in this transmission where the teeth face down as opposed to up.

[00:51:19]And you can identify the snap ring that holds the return plate in place because it's beveled and the beveled side faces up. It's actually beveled on both sides actually, so it doesn't matter. But it is beveled unlike the clutch snap ring which is flat and it has two sharp points on the ends.

[00:51:48]Now you can inspect the bonded piston if you want.

[00:51:54]All right. Now here is our little reverse clutch.

[00:52:04]that two six clutch snap ring also is beveled but it's beveled only on one side where the other one the one for the return uh plate is beveled on both sides.

[00:52:20]So that's the difference between All right, did our low reverse clutch. Now, the snap rings for the clutches for 26 and low reverse are not selective.

[00:52:53]All right, the frictions changed.

[00:52:56]These look like they have the early frictions.

[00:52:59]I don't remember the year. I'll annotate the video, but both the 26 and the low reverse clutch as well as the 35R clutch, maybe even the 1234. Um, all those frictions changed in their design.

[00:53:12]I don't know necessarily the material change but the design change the way they appear is different you know pre and post engineering change. So your oneway clutch uh rear 38 element sprag rotates counterclockwise and locks clockwise.

[00:53:31]All right. So replace your sprag element. It will come with retainer plates keepers and new snap ring here for the sprag itself. So, let me go to the press so that I can remove the snap ring and we'll look at the condition of the swag.

[00:53:45]Then, we'll get the rear gear set out of the case and be done.

[00:53:58]All right. Notice you're going to have a blind spline here on the uh housing lugs and then a corresponding blind spline on the uh inner element of the sprag.

[00:54:09]So when you're holding it like this, the inner element, the outer element will freewheel counterclockwise.

[00:54:15]Always replace these scrags. Never reuse them.

[00:54:21]You know, a lot of folks will try to save money and reuse this kind of stuff and then, you know, when they put the transmission back in, they'll have forward movement for about a second or two and then it'll neutral out. And it's neutraling out because this sprag has failed.

[00:54:43]All right. So, here is your cover plate.

[00:54:46]Then your top retainer.

[00:54:49]This, of course, is the inner race.

[00:54:52]So, you want to check the inner race.

[00:54:54]Make sure it's mirrory smooth.

[00:55:04]and then this frag itself.

[00:55:08]And that that felt a little weird to me coming out.

[00:55:12]When you have major soft part failures in the case, there's so much like, you know, fine metal grit and debris floating around, it'll score up surfaces like those for the sprag.

[00:55:25]And so if you're not sure if something feels weird or looks weird, when in doubt, swap it out. That's my motto with transmission hard parts. Don't put something back in that you're not 100% confident in that is serviceable and you know will last. Don't be afraid to swap it out. Okay. Jury is still out on this cuz it's filthy dirty. But once I have it cleaned off and had a chance to inspect it, we'll know for sure if that whole sprag gear assembly is worth reusing or not.

[00:55:57]All right. Here's your um return plate.

[00:56:00]Again, teeth face up, face you.

[00:56:07]So, our piston. Always replace your bonded pistons. Never reuse them. And you have a big fat O-ring down here.

[00:56:20]So, obviously, a new one will come in the kit.

[00:56:26]It's your big fat O-ring.

[00:56:29]So, your 26 lower reverse housing is now empty.

[00:56:35]Let's take a look at the lower reverse clutch pack.

[00:56:46]So, no reverse condition would have to be explained by fatigue and wear in the 35R clutch. But we did not see weeks there.

[00:57:00]And I don't recall him telling me he had issues.

[00:57:05]Well, I guess he did. He said there was slipping at low speeds. So, low speeds, you're going to be in third gear. So, he did have issues with drivability in um third gear as well. And of course, fifth gear is gone.

[00:57:20]All right.

[00:57:23]Next thing that I'm going to do is thread in a tool.

[00:57:29]into the uh rear gear set way at the bottom so I can lift out the entire assembly.

[00:57:38]So, I believe this is M12 175. This is just a threaded rod with a couple of um large washers, including this big fender washer so I can use it to grip. And then a a nut to lock it all down.

[00:57:57]There's a special tool uh both available from you know Kent Moore original OEM GM tools or the the aftermarket with the adapter case tool. Either were obviously perfectly fine, but this is a much cheaper solution and works just as well in my opinion.

[00:58:17]All right, I'm going to kind of take this out with two hands.

[00:58:29]This is heavy, so you just want to be careful.

[00:58:35]The rest of that fluid can drain out.

[00:58:51]All right. bearing dropped onto the bench. This is going to be our rear case bearing.

[00:58:57]Okay, this is the side that faces the case, the outer race. And then the inner race faces up toward you. Okay, this is the rotating element. So, this is the element that you want facing the rotating component.

[00:59:12]All right, these snap rings for the non-unit design can also be tricky to deal with.

[00:59:20]And so the best way to deal with them is to try to pry out and underneath with your screwdriver.

[00:59:31]It may take a few attempts to get it.

[00:59:37]And the screwdriver is ideal for it. A little bit too thick.

[00:59:52]There we go.

[00:59:55]All right. This and the other snap ring that's deeper inside the assembly are exactly the same. So, you don't have to worry about, you know, mixing them up or whatever.

[01:00:07]All right. Here's our planet.

[01:00:13]And there's a bearing.

[01:00:21]All right. I don't see too much in the way of heat stain here, which is good because this planet is not cheap to replace.

[01:00:31]All right. You have a needle bearing assembly here. There's a special tool that you can use to pop this right out.

[01:00:37]Um, it's basically a slide hammer attachment and it's got a hook that comes in here and you just wrap it out once you have it attached to the slide hammer. Pretty simple deal.

[01:00:48]All right. So, to check the planet, it's best to just take this out. And then you're going to check all your pinion gears for side play like you normally would any other uh planetary carrier assembly. And then you're going to check the sungearss and the bearings that lie inside here.

[01:01:11]And see this bearing went right here and it locates here. Well, where did this bearing come from?

[01:01:28]Right here.

[01:01:38]All right, here is the top ring gear.

[01:01:43]Check your teeth. Make sure they're not boogered up. And then you have a step side here. This side faces down. So into the drum like so.

[01:02:01]All right. Then you have your second snap ring.

[01:02:18]You're going to use more or less the same tactic to try and get up under it.

[01:02:25]though it may be helpful to have a pick as well to help you. So you kind of get it out away from the groove and then you try to get a pick in there.

[01:02:36]I mean, you get the idea. My hands are so slippery. It's just very difficult for me to actually do what I'm trying to describe to do or for you to do.

[01:02:46]If you have a hole in the bench handy, that would be ideal.

[01:02:53]There we go.

[01:02:58]So again, these two are exactly the same.

[01:03:05]Don't worry about mixing them up.

[01:03:09]All right. You're going to have a spacer ring in here.

[01:03:12]Excuse me.

[01:03:16]All right. It's orientation agnostic.

[01:03:23]And then for your bottom uh ring gear, the beveled side's going to face into the drum or the housing.

[01:03:40]All right. And then when you're trying to put your center support return plate snap ring back in, what I'll do is I'll take this thing, I'll sit it right here, kind of to one side. I'll have the snap ring in there and I'll take a real thin flatb blade screwdriver and put this in the press. I'll press down on this and then I'll wedge the um snap ring into the groove and maybe four or five lugs, you know, get four or five lugs uh captured. And at that point, I'll take it out of the press and go to the bench and finish it off with a hammer and a screwdriver to seat the uh snap ring throughout the rest of the lugs.

[01:04:24]And that's it. That's all there is to it. I have a video that shows you how to do that where I demonstrate it. If you're curious, you can check that out.

[01:04:30]It's in the same 680 playlist.

[01:04:34]So, that is the tear down.

[01:04:37]Let's get this fluid drained.

[01:04:43]I'll deal with the shift and parking linkage and whatnot later. Um, for all 6L80s, any year that you're working on, unless it's 2018 or later, I would strongly recommend that you update the parking rod assembly to the OEM GM heavyduty version that they started to produce for the 2018 model year. Okay? It'll retro to any year 6L80 and you will prevent another risk from materializing, which is having the parking pole itself separate from the rest of the rod due to the failure of the little rivet on the end of it. All right. To my knowledge, these are the only GM transmissions that have this issue. And it's a common pattern failure enough to where there's bulletins on it and everything. So, you know, you're going through overhaul, you want to make sure you tend to that as well.

[01:05:43]All right, this was a satisfying tear down. Satisfying to the extent that I was able to pretty much tie all of the drivability symptoms to direct causes inside the unit. We got a smoked, and I mean smoked, 456 clutch that had collateral effects, I believe, for the 35R. So, he had uh no 456. He had no reverse and he was slipping in third gear. I mean, uh, what he said to me was in his exact words is the thing is cooked. And he was right. So, um, we're going to need a whole I'm going to replace the 456 clutch drum. I'm not comfortable reusing that drum given the amount of heat soaking plus everything in it. Uh, all that stuff's got to be replaced. Um, we have to go through the pump like we normally do. Um, we're going to install a 2009 and up stator shaft or a whole stator stator support assembly, whatever I can dig up. Uh, we have to still go through the valve body, vacuum test that once it's cleaned off.

[01:06:43]And um, we also have to replace the um, or not replace, but uh, weld reinforce the 35R drum. It doesn't need to be replaced. It just needs weld reinforcement. All right. Well, that's the tear down, guys. Thanks so much.

[01:06:59]greatly appreciate you spending time on the channel. Hopefully it was informative for you or if nothing else entertaining. If you have any questions, comments, go ahead and leave below. If there's anything else you want me to, you know, focus on when it comes to 6L80s or '90s, I'm doing these transmissions more and more, so just put a suggestion down there in the comments and I'll prioritize a video as soon as I can. All right. Well, thanks again for watching. I greatly appreciate all your views and support, and I look forward to seeing you on the next one.