LT77 Reverse stop

Added: 2026-05-09

[00:00:00]Morning.

[00:00:07]It's the 7th of May. Um, as you can see on the bench here, I've got an LT77 that I found on the shelf. I'll put a picture of here when it's on the bench, but this is how I found it. Must have had it 18, 20 years. I was stuck for some shims. Anyway, I've got the shims now. So, I thought, well, seeing I've got a lot to do, I might as well strip it down, clean it, and have a look at it. Because I actually put a brand new shaft on it, and it's cleaned up really nicely. There's nothing wrong with it, and none of the parts were wrong. But I'm in a bit of a dilemma. Should I do the full video of stripping it down and building it back up again? We've done LT77s before. Maybe an update 2026 might be a bit better. I don't know. But it's going to take me about 3 or 4 hours for editing. And if I only get like 100 like 500 views, is it really worth it? I don't know. You tell me. Cuz time's money, isn't it? Anyway, the the the moral of well, not the moral, but the point of this exercise this morning is I had an email from a chap who said, "These aren't very well thought out gearbox because you can select reverse as in instead of first."

[00:01:22]And he said when he's going uphill, it's easy to put into reverse.

[00:01:26]These remotes here are the same casting as an R380.

[00:01:34]So the LT77 and the R380 is exactly the same casting. Nothing changed except around about here there's a little fork that's attached to the underside to keep the uh fifth gear in place. Well, like for for selection and things like that on the R380. If you have a look underneath it on underneath this on the R380, that piece is missing. Very important.

[00:02:03]But otherwise, it's exactly the same.

[00:02:05]This is the last one I've got. So, when I sell this gearbox, it's not going with this casing. All right. This this aluminum casting. Now, as you can probably see about here, >> you can see there's a metal plate there.

[00:02:17]But it's not just a metal plate. It's a pin. And that pin is the stop for the fifth. All right. So, if we were to put this into fifth like that, because the ball's at a pivot like that, it's hitting the pin, so it can't go any further. You got that? Let's move to the other side. This one here is the reverse stop.

[00:02:46]You hear it clunk into reverse? They always clunk into reverse. There's no synchro mesh on these. How they managed to clout it into reverse when they're going uphill, I don't know. Anyway, that's that's another story. Reverse.

[00:02:57]Now, you can see here that this is the reverse. All right. So, when it's in reverse, uh this some parts of this are missing. This is it here. So, I'm going to put this one on here. But hold on.

[00:03:11]I'm going to take this apart and I'll show you how it works. We'll go to the bench and I'll show you. Clean it all up. Um, but there are some shims just behind these two bolts. Very important.

[00:03:24]That's to get the tension right on here cuz they these are a funny little damn thing. Um, yeah. So, what I'm trying to say is maybe maybe be because they can select reverse kind of easily.

[00:03:41]Maybe somebody's put an R380 uh extension housing on the top but and tapped drilled and tapped the place for the fork but not put this on because on an R380 one this casting here. This isn't machined out. You can see where it is but it isn't drilled and tapped. This one is, but this one isn't. And if on an R380, this has got a nut and bolt on.

[00:04:07]See, it's kind of complicated, isn't it?

[00:04:09]Let's go across the bench and let's have a look at this. Right. So, this is the little chap in question. It's obviously been in bits before because the the nuts loose. Oh, it's come off. It's one piece spring. Ah, I see what's wrong. Why we why this is bad. It ain't got the ball in it. Got no balls. And it's kind of badly seized up. So, what we're going to have to do with this is uh soak it in some light oil and see if we can get this pin out.

[00:04:39]There's supposed to be a spring clip in here. What I'm going to do, first of all, going to put this through the sand blaster and see if we can find a clip and tidy that this up and then we'll put it through the bead blaster. I bead blasted it. I blasted everything just with a sand blaster, but I can't see a clip in there.

[00:05:00]H. So, what I'm going to do is it's very difficult to blast inside a little cavity like that. I'm going to try and get this out. We'll put some uh some oil in there and see if we can work that one out. PB Blaster.

[00:05:17]So, there's the piston.

[00:05:20]There's another spring. So, all we're short of is a ball. So now we can put this all through the the blaster, the bead blaster. Then we can calculate the size of our ball. I don't think I've got any. It's just a ball bearing, but it might give us an excuse to go and see JP for an hour. Well, all the parts cleaned up nice.

[00:05:44]They all came up uh just lovely like new. Uh the piston here is a little bit rusty, but I don't think it's going to be really bad. The springs are okay, but I ain't got a ball.

[00:05:58]I haven't got a ball at all. So, what I'm going to have to do is pop over to JP. See, that fits nice in there. Pop over to JP with this. See if we can find a ball. Now, how we're going to measure that ball? We'll just get a drill bit and see what fits in there. And then we can measure up the size of the, you know, we can calculate the size of the ball. Right. I put it in the vice.

[00:06:22]Um, I had an idea that when this goes back, the ball will drop into the slot, but I don't know how to adjust this nut here.

[00:06:41]It doesn't make much difference. So, what I'll do is I'll go upstairs and see how you calculate the shim. We know it's all together now, so we can't go wrong.

[00:06:51]And I don't know why they said they put a clip on there cuz there wasn't one.

[00:06:54]There isn't even a groove in there. So, let me go and find out the details. See if I can print them out. Then we'll fit them on that box and see if it works.

[00:07:02]Well, just before I went upstairs, I've got here the Land Rover 110 service product training. I don't know what date this is. Probably 1820 or something like that. Um, yeah, it hasn't got a date in, but this is a factory book. And I found a page here pertaining to the uh this piece here and it says here reverse gear plunger assembly. Remove the plug load spring and detent ball from the reverse plunger assembly here. Detach the circlip which retains a reverse gear plunger not in. Pull out the plunger followed by the short spring. Label all parts and keep separate from the fifth gear plunger assembly. Now, the early ones had a similar sort of thing on the other side. Later ones didn't.

[00:07:50]Fit the spring into the plunger base.

[00:07:53]You haven't done that. Wait a minute.

[00:07:56]Detachable parts. Lubricate short spring and plunger with any grease L2 or similar prior to assembly. Don't fit the spring into the plunger base and slide the assembly into the reverse gear plunger housing here.

[00:08:14]Fit the spring into the plunger housing.

[00:08:17]Oh, we've done that. Lubricate the detent ball with light oil and fit into recess. Refit the short spring and plug.

[00:08:25]Coat the plug and threads with Loctite and tighten to 22 Newton meters. Well, that doesn't tell us anything really, does it?

[00:08:37]We've got this the right way around.

[00:08:41]It doesn't tell us anything.

[00:08:45]Doesn't telling anything about the shims either. Oh well, we'll go upstairs and have a look at a bit more modern stuff rather than this written in bloody Latin. What a mystery this is turning out to be. Should get Arthur C. Clark on it. This one's off an LT77.

[00:09:00]Correct. The LT77s, the later one had a a fixed cap on here, not an adjustable one. No mention of the shims. No mention how to adjust it, nothing. But going off that one that's there, it has two shims on it. So, I think we're just going to have to wing it, put the shims on, and see how it can adjust. Let's have a go. Well, I have no idea about adjusting it.

[00:09:29]But just for the people who don't know, when you set these bias springs up here, you set it so that it goes into third and fourth. Really easy. All right. You don't do it first and second. So first is just a little bit to one side and then back to second. All right, that's how that works. Now for reverse, obviously it's across there. Now that does take some considerable effort now to push that in cuz I've got this little thing on here now.

[00:10:01]But I'm going to play around with it to see what is the maximum pressure we can get onto that.

[00:10:12]Is that reverse?

[00:10:17]Yeah, that's reverse.

[00:10:20]Is it?

[00:10:27]No, that's too much. It won't go in.

[00:10:37]Aha. Did you hear that? Yeah. That's reverse.

[00:10:42]So really, if you're just being gentle with the damn thing, it'll go in. But I can't see how you can actually crash it into first. This is kind of you'd have to physically bang it across. So I'm going to lock that up.

[00:10:58]And uh I think that's about first. That's third, fourth, first. second, fifth, reverse. Now I'll just turn it around a bit there. You can see you can hear it click in. It does take some considerable force even with my weak strength. So I think that now is set up.

[00:11:29]Um, so like I say, if you if you screw it down too far, it won't go into reverse at all.

[00:11:36]Battery's running flat. See you later.