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Does my front diff need a re-build?

MisterCruiser

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My inner cv joint casing has up/down play in it and I think this is the cause of a loud clunk noise I get this past yr or more.
Is it difficult to rebuild the front diff? I see Roughtrax have a rebuild kit which I'll likely tackle with a friend, appreciate any tips from members that have rebuilt theirs before.
Which bearings in the kit are the ones that the inner drivershaft splines roll on?

Would worn driveshaft bearings where the shaft enters the diff result in a loud clunk particularly after having sat overnight and when first set off making a little turn out of my parking spot.

See pics below to describe what I've found having removed the passenger driveshaft.

Should I have up / down play on the tripod casing?
Is that bearing rub mark highlighted in pic just normal mark or is it a sign of something not running straight?
It's not very obvious in the pic either, but there a little blue marking at the inner spline end of the shaft and also some of the splines look a little bit rubbed, but not bad at all, but could all be a sign of bad bearing and not running straight I'm thinking.

Driveshaft-Passenger-side-Inner-CV-edited.jpg



I removed the dust seal from the driveshaft outlet of the transfer box, but I don't see a bearing that I can remove from the outside, is it inside?
Is that piece with the holes in it a bearing?
It's not easy to see in the pic, but there's 2 score marks highlighted, are they a sign of something not running straight?
Also, there a sharp / razor like edge on the bottom semi-circle of the outlet hole highlighted in pic, this suggests the driveshaft isn't running straight and rubbing the surface?

Driveshaft-Inlet-Hole-edited.jpg
 

flint

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Have you drained the diff oil ? If so, was there much in the way of bits stuck to the drain plug ?
It's not a particularly hard job to rebuild, but (quite a big but) not that easy either. Because it's what's called a clamshell diff (i.e. the casing has to be split to get at the innards), the rebuild involves removing the diff from the vehicle. I've only done this job on a petrol Collie, but it was a bit of a fiddle to get off (and back on), it's a while since I did the job, but I can remember a fair bit of grunting and foul language. The setting up of the pinion to the crown takes longer as you basically have to reassemble the case to check the contact pattern, adjust with shims if needed (probably will be needed, allow a day or three for them to arrive), split the case, check pattern again, measure backlash, torque the crush tube up, etc. etc..
 

MisterCruiser

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Haven't drained the oil yet as I'm debating what to do, not sure if I'll stick it back together and drive it on until for another while or fix it now. Or do I buy a 2nd hand diff or rebuild mine, etc. etc.
The oil that drained out with the driveshaft removed is all clean and gold. I might drain it now anyway and look at the magnet as it's only a litre to re fill it. Edit: I drained it there now, oil is perfect, golden and magnetic drain plug is perfect too.

Can we say from my description of the up / down play that my diff definitely has a problem?
Can I check the bearing by hand with the driveshaft removed? What's the part near the outside of the driveshaft hole with the holes in it, I assume them holes are to allow oil to get around it, but what is that piece?

Possibly stupid question but can I run the cruiser with the diff removed, if I just disconnect the propshaft from the diff to the transfer box? Does it actually require a diff to drive?

Also, does anyone know will the diff from the newer 2003-2010 model LC3 120 fit my cruiser, are they the same diffs?
 
Last edited:

Shayne

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Not sure if i'm understanding your description but it sounds like a buggered cv to me which is rare for the 90 series but nothing lasts forever , personally i'd replace the whole thing before worrying about the diff .

 

MisterCruiser

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The inner cv joint itself might be buggered, good thinking. I'll remove the boot and get the tripod cv joint checked.
 

MisterCruiser

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It's not the inner CV joint, it's fine, checked it today. Or the outer Cv. I spoke to 2 gearbox / diff repair lads today too and both have ruled out the front diff as well based on what I explained to him.
So, it's back to the drawing board.

So, basically, I've got a loud clunk, almost like a really loud sharp Crack sound, but only does it mainly "once" a day, first thing after the cruiser has sat overnight.
Also, I think it's starting to do it (although not as loud) when slowing down and turning into a driveway where the front wheels go over a little raised surface where the road / driveway surface meet.

I had another look at the prop shafts, bushings, engine mounts, body mounts, springs, shock mounts, wishbone bushings, ball-joints, etc., and can't see anything obvious. Is there only 2 engine mounts on these 90 series? Where are they detailed in the workshop manual, I can't seem to find them in it.
 
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AndyCook

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What about brakes, if it happens when you first move vehicle, pads could be sticking to disc and releasing with a crack noise
 

Shayne

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Crack like a hammer against the frame ?

If so it rings a bell and i eventually worked out that while the lower wishbone bushes will likely never wear out or fail an mot they allow the bone to slide back and forth knocking between the frame brackets . That it only happens sometimes makes it even harder to diagnose .
 

MisterCruiser

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I put the driveshaft back in and filled the diff, I'm just gonna keep driving until it gets worse, doesn't affect driving at all.

I checked the lower wishbone bushings as suggested and they seem ok, no real movement with a pry bar. It's not like a hammer against the frame, it's hard to describe, best way I can describe is like a loud dry crack, I'd suspect ball;joints, but they seem to fine, not too old either, both replaced in my ownership.
I don't thinks it's brakes as only happens when turning, after sitting up, mostly. However, I got it to do it a 2nd time the other evening by just doing what I done the first time, slow turning manouver, but I couldn't get it to do it when driving around in a complete circles in 1st gear, etc...

I'll double check during the week if it does it as constant when driving forward from its parking spot instead of reversing, think it did, but need to double check.
Think I'll just have to leave it until it get's worse and easier to diagnose.
 

MisterCruiser

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@ Raj - Cheers for the thought / link. I don't think my 90 series has them turn stops, that looks like a pretty heavy duty set-up. I'll have a gander though.
 

chapel gate

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I put the driveshaft back in and filled the diff, I'm just gonna keep driving until it gets worse, doesn't affect driving at all
The technical term for this is;
LID.
Let it develop..
 

Shayne

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Take your anti roll bar and drop links off you don't need it any way and i have in mind a dry ball joint rusting solid and cracking free . While i struggle to imagine it being loud drop links are ball jointed and prone to rust .

The arb itself could be rusting to the bushes .
 

SteveJB

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Not sure if you have done this already but change the way you park up overnight so if your usual way is drive in and reverse out reverse in and drive out unless you are on a busy main road to do it safely are you on coils possible springs settling back in or if torsion bar front mounts have a crack some upgraded kits came with reinforcement plate that attached to lower wishbone could be a crack behind reinforcement plate best of luck
 
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