Thread: 91 Disco V8 LT77 to R380 Swap Pictorial

Well i've had these photos on my computer for a couple of years and finally got myself motivated to post them. Taken with a camera phone.

This was my first rover, and 4x4. And im still learning mechanically.
Bought cheap off ebay with a known gearbox problem (bang at lights, then no drive), i started by taking the box out to see what was wrong with it, thinking i could maybe fix it, soon realized rebuilding it myself was too much for me, and bought a replacement box and tc from a wrecker (D2 V8 R380 & D1 LT230), though if i had my time again i would have but the project on the back burner and waited for cheaper parts to come up.

Apparently input gear not cross drilled back then and ran dry...

This is not a complete guide, more just photos of main points along the way with descriptions, and possibly isnt the best/safest way to do somethings, though i followed the workshop manual when applicable.

In the end i had to do the job twice, as once installed initially, noises indicated clutch/thrust bearing problems that i didnt pickup when i had the box off first time. so took it back out and yes clutch had broken spring and was told that should be replacing thrust bearing with new while in there.

As i had not much knowledge about this particular exchange it took me some time with plenty of calls back to the dismantler's asking why this or that doesn't fit...



First up, jacking & drop old box out with engine hoist:
(the second photo here is actually from when i took it out the second time to replace the clutch, spigot & thrust bearing, but you get the picture) with one side bricked up, i dropped it on some lino, then slid it out from underneath






Next Box is out, time to split it and find out whats wrong:



Gear Box Output Shaft & TC Input Gear: (stripped)



Funny thing was, this was the first time id seen this far inside of a gearbox, and had to post these photos on the boards here to find out yes indeed, they where both totally stripped...

As already mentioned, went with replacement box's rather than rebuilds... i just didnt have the tools, time or experience to do a rebuild

Here is the new box's though the gearbox already has the old stick shifter in it. this was one of the few bits that could put this post into conversion territory out of straight swap over.


To get this in i had remove the shown parts from the underside if the old shifter, as they are not needed and dont fit: (once the pop rivets where drilled out of the black plate, i put fresh ones back in the holes in the shifter to seal them up)



I then mounted the old Transfer Case (LT230) shifter stick/box, and old diff lock lever pivot.



Next a couple of photos relating to the reversing lights switch:
In the old LT77 boxes reverse was left of 1st, an easy way to identify that you had one of these was simply by looking at the gear shift knob pattern.

Also the switch was in the shifter box, while in the later R380 the switch is in the gearbox housing itself, shown in second photo with pink tag attached. I

If i recall correct i left the original mechanisms in place as they didnt get in the way.



Ill jump ahead now and mention something that happened at the end of all this but is relevant now as i wish id checked it out at this point.

I just wired a new set of plugs onto the R380 reverse switch wires and corresponding car loom wires. Now when i get it all together i tested it, rather than before. Im not sure what was wrong though, the switch or some difference in how a discovery 2's reversing loom is setup. But it didnt work, the switch showed it was working on the multimeter and the light circuit worked but whenever you put it in reverse no power flowed through the circuit.

Looking at the circuits for the D1 and LT77 it looks like the whole current for the lights flows through the switch itself, and it seemed like the switch worked enough to look good on my multimeter but as soon as you tried to run any real load through it it cut out... maybe a faulty switch or maybe changes in how its used.

As i said, now is the item to check these things as once the box is in i found out its too hard (for me) to get the switch out of the side of the gearbox.

Luckily i worked/hacked around it by making the R380 switch, switch a relay that switched the real load... i mounted the relay at the firewall, where the wires comes up from the gearbox just before they go into the cabin on the passengers side.



Next is the transfer case, Discovery 1 LT230. This one had an electronic sensor for speed, so this had to be swapped over for the cable used in my older D1 (easy enough)



Now the Transfer Case Levers, (High/Low & Diff Lock)
Once again another change, and a custom part from the wreckers. Layout changes mean a new diff-lock lever:

(New and Old)



First is old High/Low fitted, Then new Diff-Lock fitted:



Then back to the old box to pinch the handbrake system:




Only problem is they changed things again with the later LT230 install and the handbrake actuating level mounting bracket needed to have 2 of 4 needed bolt holes drilled and tapped:



This went smoothly enough until i found out the hard way that alloy is to be treated very gently, as i stripped the new threads i'd just tapped ! yay ... So i found out about the wonderful things called time-serts and put two of them in, this time much more carefully:



Ok, almost there (or so i thought) and proceeded to reinstall the whole thing. Got it in there with the mounts attached and went to attach the gearbox oil cooler pipes only to find out they had also changed the thread on them... so re-detach and lower back down:

Firstly the offending part, pre install (then was the time to change it)



Then, stripped one of the bolt heads trying to remove the old part and had to angle grind the head right off, but got the cooler part off with little damage and swapped over with little trouble:



Then put it all back together as much as was needed to test it, and found there was a clunk whenever pressing the clutch in (with engine running).

Told its likely the thrust bearing or clutch both of which i should have checked out while i had the thing apart, so back to the shed and drop the box down. Yes both need replacing. So did that and put a new spigot in too.

Here is old clutch with broken spring, as well as my home made clutch alignment tool which worked great, i just shaved off enough dowel at the end for it to fit in spigot, and wrapped enough masking tape around the dowel to fit snuggly inside the clutch whole and i just saved myself nearly $60 at repco (these tools aren't cheap i thought...)



All good, no more noises and its driving great, just one more thing which once again relates to changes between disco models.

There's a little inspection plate/gap at the front bottom of the bellhousing, and they changed the bolt whole locations, and actually scrapped the plate altogether instead building into the sump/engine instead apparetly.

So a couple of the old plate holes line up, a couple more do once drilled out bigger (as the bolt hole size changes too) and the rest are just sealed up as is a few gaps still there onec installed (its not a perfect fit but usable):



And that's about it (photo wise) as there's a lot more to it in between the photos and after that you can read about in the workshop manual.

But one mistake i made which you may pickup from the last photo ? can you see it ???



Yes, i put the clutch slave cylinder in wrong and never realised, just always wondered why it was near on impossible to bleed.

Prob a year down the track, after having to replace it with a new one i realize that the nipple needs to go in the higher hole and the fluid pipe in the lower, so that the nipple can let out the air which sits at the top of the cylinder as air does....

That's all i can remember right now except i had fun testing it all out

Good write up, and some good pics, especially the gear lever bias springs and plate. I'm sure when some one has the problem with gear selection due to a twisted bias spring plate, your pic give a clear pic of what they are all about.
I fitted a D2 transfer box to a D1 and had to use the old rear housing to put a speed transducer, there was no hole drilled.
You were lucky you had a straight swap