hot diff judder

[wads]

Anyone experienced a judder from the rear end when pulling away from a standstill when the diff is hot, not there when cooled down. May be the oil type ?
cheers

[dannyboyo]

Yep, got this happening right now!!

I had the diff bearings changed a while ago and it was refilled with a synthetic gear oil (not Mobil 1 though). I only get a judder after say, 5 or 10 miles of driving. And only if i'm not going in an absolute straight line.

I took it back to the garage and the engineer said it could well be the oil, but I'm still not convinced. I have to take it back some time soon, just need a day off!!

Can't see how the wrong oil could create such a judder at low speeds (up to say 20-25mph), but thats all I'm hoping it is!!

[.Mark]

I get that too. I think "They all do that, Sir".
I posted about this some time ago and I seem to remember Steve Heath writing back saying it wasn't unusual so I don't worry about it now.

[joospeed]

you're all on BTR diffs then? .. seems to be the thing to have wrong at the moment.
The BTR diff is virtually bullet proof apart fom this thing .. it's something in the LSD that gets heat affected.

[iandbeech]

Does it give a feeling as though you have rear wheels shaped like a 50p (or threepenny bit if you`re really old!) but literally on start off as releasing clutch?

[dannyboyo]

iandbeech said:

Does it give a feeling as though you have rear wheels shaped like a 50p (or threepenny bit if you`re really old!) but literally on start off as releasing clutch?

Mine feels like I'm driving over cobbles, and I've got a GKN diff by the way.

You sure yours isn't an unevenly worn clutch? A couple of months back mine was diagnosed as having a couple of clutch plate springs missing causing the plates to be not quite parallel and a judder when pulling off with the clutch still semi-depressed.

[iandbeech]

dannyboyo said:

iandbeech said: Does it give a feeling as though you have rear wheels shaped like a 50p (or threepenny bit if you`re really old!) but literally on start off as releasing clutch? Mine feels like I'm driving over cobbles, and I've got a GKN diff by the way. You sure yours isn't an unevenly worn clutch? A couple of months back mine was diagnosed as having a couple of clutch plate springs missing causing the plates to be not quite parallel and a judder when pulling off with the clutch still semi-depressed.

Don`t think so - the clutch was checked about 1500 miles ago and all ok. Driving over cobbles is a better descrption than my 50p though!! Its in for a major next week so any problems will soon be found.

[tvr_griff_4000]

Mine did this and it was the internals being carboned up. (Mustnotthrashcar). The garage stripped the diff out, cleaned it up and put in some new Castrol diff oil that came straight out of their technical dept. They knew of the problem. Supposed to solve the problem of the diff getting too hot.

[wads]

Mines a 95 Chimp with I think a GKN diff. It feels exactly like slop in the universal joints on the drive shafts, definitely at the back of the car. I would have thought that there is some form of clutch mech in the diff, in which case hot and thin oil may cause this. Thanks for the comment about it being the way they are, the diff expiring at high speed crossed my mind a few times recently whilst on the Le Mans trip.
I'll change the oil and let you know.
thanks

[trefor]

I had a similar problem, only when pulling away from standstill when the diff had a chance to get hot. Needed a new crown wheel and pinion due to a hairline crack only showing under extreme heat (had the diff rebuilt once, which fixed the bearing whine probs, but the judder was stll there - reconditioner had to look hard to find the CW&P fault).

T/.

[dannyboyo]

trefor said:

I had a similar problem, only when pulling away from standstill when the diff had a chance to get hot. Needed a new crown wheel and pinion due to a hairline crack only showing under extreme heat (had the diff rebuilt once, which fixed the bearing whine probs, but the judder was stll there - reconditioner had to look hard to find the CW&P fault). T/.

Sound horribly like my problem! Except the judder only appeared after I had the bearing replaced. I heard it's a nightmare getting parts for the GKN diffs these days as they have been discontinued.

Do you mind me asking the sort of money you payed for a new crown and pinion?

[trefor]

'bout 400 notes I think. But you need to strip it out/put it back in the car again so it will cost more. I had the problem before the first rebuild, hence only cost the parts the second time around.

T/.