The V8 Owners Forum -

I thought I'd ask here, I know it's a V8 forum, but I guess some of you might have used Range Rover axles or diffs and be able to help me.

When I'm driving, say I have the car in 3rd gear (3.9 5 speed manual range rover), and I'm coasting, if I apply the throttle smoothly, I get a bit of a good clunk from the diff's, the car has nearly 95,000 miles on the clock. If I apply hard throttle, the clunk is worse.

My question is... a friend of mine with a classic also, tells me I can disconnect the driveshafts, and tighten the diffs by tightening up the but inside the top of the diff. Is this rubbish or true? I'm a tad sceptical.

If it is great, if not, is there anything I can do apart from simply replacing the diffs?

Thanks

It almost certainly isn't the diffs.
Check all the suspension bushes, and in particular the top balljoint on the rear axle. Often that wears, and the axle moves about when under load.

Also halfshaft splines can wear.

And also I'm not sure about the transfer box you have, but the chain drive one gets a stretched chain which has slack in it.

And as far as I know, you can't adjust the diffs (at least, not as a DIY proposition).

Chris.

Hi Chris,

Thanks for your response. I do hope it isn't the transfer box, I was around when my mate changed the auto box in his and it wasn't the most fun job about

I'll check the rear bushes thoroughly, including the one at the top of the rear a-frame, I think this is what you're talking about? I'm about to renew the rear trailing arm bushes, it'll be nice to see what that does for the handling, it's supposed to firm it up a little if the old ones are worn, and mine are most definitely worn!

Can you elaborate on halfshaft splines, are these what run from the diff to the CV joints? I don't know a massive amount about drivetrain components, but I'm a keen learner

Thanks again

Sorry Chris, dont want to stamp on your toes here. The halfshafts have splines that go into the diff on the rear and splines either end on the front axle which go in the diff and the cv joints. These can wear but more likely your props splines have warn where they slide together. Are they greased up? You do get a little backlash off the diffs with wear but never heard of tightening them up unless you take out shimms but i wouldnt like to try it as a diy job as the crown and pinion have to be lined up proffesionally. I have just polybushed my disco and it got rid of all knocks and bangs. You can check your props by holding half in one hand and try twisting the other half but better to do this with one half off the car. I would try filling them full of grease first. Has your transfer got oil in? Does it do it in low box? Any transmission e.g props, giffs etc will be worse in low box as theres lower gearing and more instant stress on your parts, oohh eeerrr.

well done for making me think of that actually, it's terrible in low box, much worse, there's a LOT of slack. I can't believe I hadn't thought of that lol. So it definitely sounds like driveline / transmission then. Bugger. Ah well, sooner I work out what it is, sooner I can repair it.

Good point about the propshaft splines.

Thinking about it, the 3.9's almost certainly had 24spline half-shafts, which are less prone to wearing.

But to check them, you just have to undo the 5 bolts in the middle of the hub and withdraw the halfshaft. You have to take the wheels off first.

Then inspect the inner end and see if the spines look worn. You'll get oil escapeage when you do this!.

But I'd definitely go for axle location as being the most likely problem.

I'd get a Haynes manual, they've got good descriptions of the various bits in the axles etc.

Yes the balljoint is in the apex of the a-frame.

You'll probably find that there's lots of things with a bit of wear, and it all adds up to a hefty clonk!

Chris.

ChrisJC wrote:Good point about the propshaft splines.

Thinking about it, the 3.9's almost certainly had 24spline half-shafts, which are less prone to wearing.

Older 3.9's have 10-spline half-shafts. The newer 24 spline came relatively late, around 93-94 - if I remember correctly.

That seems right Timo, after some research, the 24 spline diffs are in some VERY late 93 cars, and the 94 and 95 soft dash models.

Mine will definitely have the 10 spline diffs it appears.

In that case it's worth sliding out the half-shafts and checking their inner ends. You can only do the outer shaft on the front axle as the inner shaft involves dismantling the swivel, not really worth it unless you're doing some other work there.

Chris.

Ive got two 10 spline diffs here if you need one or two? £50 each or you can have them both for £80.

Not unusual for a 10 spline diff pinion to rotate 1/8 to 1/4 of a turn with freeplay in the diff/ splines etc.

A Frame balljoint has gone.

It happens with regularity on all Rangies

A-frame balljoint is a good candidate.

Other could be the gear box mainshaft vs t-box primary gear splines. It's common with Rangeys and Discos with LT77 and LT230 - a known lubrication problem. Not so sure if it exists with B&W t-box, but the chain slack surely does.

A friend of mine blew his LT77 main output shaft and the t-case primary gear splines on his Disco a couple of months ago. Before that he had a lot of slack (other possible places were taken care of earlier). He put in a re-con LT77 and a new cross-drilled t-case primary gear - slack gone.