Rebuilding LT77 5 speed - options and questions

**MacMan** · 10th April 2008, 07:55 AM

The gods were kind yesterday and I was the lucky recipient of a very cheap (free) old LT77 (thanks again!!!) which I am informed needs bearings replaced.

The box shifts and turns over in all gears by hand, but has rumbling bearings.

Since the LT77 in the Disco still works but increasingly the Girlie is finding it hard to drive (and I am finding it harder to let her drive it because she is used to her 5 speed Commodore rocket) I thought I'd have a crack at rebuilding this one myself.

The current box in the Disco is a short stick 53A prefix, and the suffix looks like a badly formed B rather than H (although H is more likely to be correct give it is one of the very last '93 vehicles). The spare I now have is also a 53A, D suffix, which according to Ashcrofts is the weakest of the LT77 boxes.

So, to the questions!

1) Given that this spare is supposed to be the weakest type, is it worth rebuilding? Remarkably, the output shaft is in near new condition, whereas the shaft on the one in the Disco is more than half toasted.

2) I am seriously considering undertaking the rebuild myself since I have a running vehicle and there is no real urgency to have a working box right at this time. While the synchro's are lazy in the one in the Disco and there is no bearing noise I think the worn output shaft will be the death of it. I put in a new cross drilled transfer gear and that tightened things up for a while, but the increase in slack indicates that bad things are happening.

R380 cross drilled gear thingamybob
This shows things as of 20,000km ago, pre new gear.

3) I have the WSM for the Disco which details the specialist tools required, and various tolerances and clearances. However, these are for the original box fitted to the Disco that I have, not necessarily the D suffix box which I think must have come from a Rangie or early Disco. Where should I look to find the correct specs etc? Are there any of the special tools I can't go without?

4) I am anticipating more than just bearings required for this job, so where is the best place to order parts from? Karcraft? Somewhere in the UK? Dare I even contemplate LR dealers?

Thanks in advance. I plan to document this both in stills and movie to post on here for all to see - looking forward to getting my hands grubby on it.

**cmurray** · 10th April 2008, 10:11 AM

Macman,
I rebuilt the LT77 in my 90 when I put the V8 in. It was fairly easy to do. As for special tools, I made one, as it was a bit of straight metal with two holes in it, and a bolt through one that was used to stop the layshaft spinning while undoing the nut on the back. I used a wheel puller to pull the 5th gear extension housing off, and this pulled the collar off that the seal runs on. I also used a bit of metal pipe to knock 5th gear onto the main shaft. You will need access to a press to press all the bearings off and on. Check all your syncro rings and I would at least replace the one on second, as that is the one that apparently has the hardest time, that is what someone told me when I rebuilt mine.

**Bush65** · 10th April 2008, 11:27 AM

I found the selector mechanism (inside the main casing) tricky to get right, when I didn't take enough notice during dissasembly, of the way the parts were orientated.

**MacMan** · 10th April 2008, 01:01 PM

Made some calls today and found some interesting things.

I have found two R380s, both with around 150,000km, as is for less than $1500 each. Considering that they are supposed to be a better and stronger box, and I can easily chuck $1000 worth of parts at the LT77, this is getting to be a dilemma!

**100I** · 10th April 2008, 01:26 PM

Originally Posted by MacMan

Made some calls today and found some interesting things.

I have found two R380s, both with around 150,000km, as is for less than $1500 each. Considering that they are supposed to be a better and stronger box, and I can easily chuck $1000 worth of parts at the LT77, this is getting to be a dilemma!

If the car is a keeper (and it sounds like it is) I'd go the R380, but I'd still re-race it, bearings aren't all that much.

edit. But maybe have a good look at the free LT77 first and see if it needs anything, it might already have had a rebuild with updated parts if it looks to be in good shape as you say.

Then if it needs ANYTHING that costs, I'd look at the R380 again.

**MinniTheMoocha** · 10th April 2008, 10:10 PM

I plan to document this both in stills and movie to post on here for all to see - looking forward to getting my hands grubby on it.

Would love to know how to rebuild the gearbox especially if you end up getting the R380.

**Hymie** · 11th April 2008, 09:44 AM

I wanted to put an R380 in mine when my LT77 died in Kunnunurra.
A Perth based Landrover specialist told me over the phone that the 380 will not fit without an adaptor kit that is not available any more!

**MacMan** · 11th April 2008, 10:54 AM

Might be the case for a 200TDI, but all the V8 mounts are the same. Straight fit to 3.5s and 3.9s as far as I know, provided the original box was a V8 box - the input shafts are different between the TDI and V8 boxes.

**Bush65** · 11th April 2008, 12:41 PM

Originally Posted by Hymie

I wanted to put an R380 in mine when my LT77 died in Kunnunurra.
A Perth based Landrover specialist told me over the phone that the 380 will not fit without an adapter kit that is not available any more!

That is correct for a 200Tdi defender - very short LT77. That now unavailable, R380 adapter kit shortened the input shaft and bell housing etc.

Disco 200Tdi has a longer LT77, similar to R380.

The 200Tdi engine was also different between defender and disco.

Disco and defender with 300Tdi use basically the same engine and gearbox. Some tuning differences, and hoses, but that is about all AFAIK.

Thread: Rebuilding LT77 5 speed - options and questions

Thread Tools

Rebuilding LT77 5 speed - options and questions

Bookmarks

Bookmarks

Posting Permissions