M3 Diff and Clutch Problems

[jpboost]

I'm currently looking at buying an E30 M3 I've been offered (I've got a thread about the car in the general section).

The diff makes a whirring noise when coming off power. I.e when rolling in gear but not accelerating. As soon as you put your foot down it seems to stop. The noise almost sounded like most cars do when in reverse.

How nasty (expensive) could the diff problem be? If it's really bad, how much to 2nd hand M3 diffs go for?

I'm assuming it's the diff as the noise seemed to be coming from behind me, kinda under the rear seats. Is there anything else it could be?


The clutch release bearing sounds very noisy (noise stops when you press the clutch). What should I allow (ballpark figures) to get this fixed.

Thanks

[ian332isport]

The diff just sounds like it could do with a rebuild. They are actually quite robust units, so a bit of noise does not meen it's going to fail immediately. I had my diff rebuilt a while back and paid around Ԛ£200.

As for the noise at idle - ignore it. It's not the release bearing. Some people say it's the lay shaft bearings, but I'm not convinced this is the case.

I personally feel it's a feature of the Getrag gearbox. My 325i Sport box did it when I bought it, and was still making the same noise 30K miles later. My current and previous 6 speed E36 M3 box made exactly the same noise. I have even read that some people had gearboxes replaced under warrenty because they made this noise when virtually brand new. Apparently it's just the gears inside the box 'chattering' against each other when there is no load. As soon as you press the clutch, you stop driving the input shaft, and the noise stops.

Apparently there was a similar issue with some older Vauxhalls (Carltons etc) that used Getrag boxes. Vauxhall introduced a special oil to quiten it down, but it's sadly no longer available.

Cheers,

Ian.

P.S. Are you the same jpboost as on Talk Audio ?

[jpboost]

yep it's me from talkaudio

I see what you're saying about the noises not being too much of a problem.

But I'm sure they are way louder than they are supposed to be.



I suppose I should try to go see another one to check it's normal...

[mysteron35]

I would agree with everything Ian said , all these boxes are noisy at tickover and will go on for a long time as long as they have oil .
Steve .