Diff on it's way out???

[Painey]

How do you tell if the diff needs looking at, I mean are there any tell tale signs I should be looking for?

My reason for asking is that there seems to be worsening 'clunk' type noise when I go to pull away around town/parking etc. Obviously griff's aren't the smoothest of beasts at the best of time but I'm sure it was never this bad before and it seems to be getting worse. I've also noticed a couple of spots of oil on the garage floor that would have come from that area.

I'm hoping this isn't a sign of bad things to come as I'm really hoping to modify the car in the new year and up the power considerably, so should I be worried? If it matters it's a late 95N reg with 36k on the clock!!!

Many thanks in advance - Chris

[Podie]

A clonk usually signifies something isn't right. Without hearing it, I can't really tell, but I'd get it checked out.

Could be a wheel bearing..?

[Seasider]

Could well be the Bushes, my top rear Bush had gone & had loud clunk.......

See here www.pistonheads.com/gassing/topic.asp?h=0&f=9&t=137182

[tegriffic]

Generally if it's the diff going or a leak you might experience continious noise such as a wine. A clunk certainly indicates initial movement and therefore is likely the bushes. Had the same, easy to fix and cheap.

[Painey]

Thanks for the replies. I certainly hope it is easy to fix and cheap because Christmas is costing me enough already! I think I'll keep an eye on it and maybe take it up to Austec sometime son if it carries on getting worse.

Cheers - Chris

[Seasider]

tegriffic said:

A clunk certainly indicates initial movement and therefore is likely the bushes. Had the same, easy to fix and cheap.

If you dont mind me asking how much did it cost Shawn ?

[GreenV8S]

I agree its the bushes are the most likely cause. I've also had similar symptoms caused by the bolts between the diff and the inner CV joints working loose allowing a small amount of play. I've also had much worse backlash caused by a badly worn diff, but in this case the hideous noise from the diff left me in no doubt where the fault was.

[Painey]

Thanks for the replies. I certainly hope it is easy to fix and cheap because Christmas is costing me enough already! I think I'll keep an eye on it and maybe take it up to Austec sometime son if it carries on getting worse.

Cheers - Chris

[TeGriffic]

Seasider said:

If you dont mind me asking how much did it cost Shawn ?

Well I don't think it was shown as seperate on the invoice but Austec did it when they dropped the diff to get to the upper seal that had a slight leak at the time, so I had the bushes replaced aswell. When they were giving me the quote they said that repairing the diff seals was a couple of hours at most so I would think that simply doing the bushes would take less. I'll find the invoice though, and if labour is shown seperately, I'll let you know.

[Seasider]

Don't worry mate... i was quoted 5hrs by a couple of people ....

Think i even managed to do them quicker than that...

[DustyC]

Exactly what bushes are these? Whats there function/location?

Cheers.

[Steve_T]

I had a problem when in France for LM 2003, where one of the diff bolts had worked loose. There was a clear thump sound from the diff area when coming on and off the accelerator. Your problem could be as simple as this, so don't worry unduly.

Steve.

[k77-widow maker]

Does it "cluck" when you engage gear out of interest, or is it when you pull away. Only mine clucks when i engage gears, and it's simply a dose of a dragging clutch, and had done it for all the time i have owned her.

[DustyC]

Mine only very ocassionally clunks when pulling away.
Been through 2 services and told all is ok.

Come to think of it, it hasn't done it for ages so perhaps it was sorted at the last service.

[GarryM]

Mine too. I've just had the diff bushes replaced and there is still a small 'clunk' every now and then. As far as I am aware this is described as (a small amount of) diff backlash. I had the option of having the diff rebuilt when the bushes were being done but I'll leave that until I actually have a problem. By all accounts some diff backlash is very common.

[DustyC]

Come to think of it I first noticed it after a track day. Since then only after long or hard drives.

Im guessing that its the noise of backlash when the diff oil is hot and thin.

Probably the reason I haven't noticed it lately is because the roads are too greasey to be going faster enough to considerably thin the oil!

[k77-widow maker]

DustyC said:

Come to think of it I first noticed it after a track day. Since then only after long or hard drives. Im guessing that its the noise of backlash when the diff oil is hot and thin. Probably the reason I haven't noticed it lately is because the roads are too greasey to be going faster enough to considerably thin the oil!

The oil should not be that bad mate, as Andy changes it on big services.

[DustyC]

"yeah I know"

But it was definitly very thin on the Silverstone GP trackday. Drive into Topcats pit garage to ask about a few things and that was the word from them.

Stopped for a decent cool down and all ok.

[Seasider]

DustyC said:

But it was definitly very thin on the Silverstone GP trackday.

Adam do you know what oil was put in last time? it should be 80/140 weight oil for a BTR diff

[crankedup]

Clunk clunk turned out to be a couple of engine mount bolts on mine. £65 to tighten and checked over all the other stuff for me