Juddering

[dannyboyo]

I've just had the diff rebuilt on my beloved Chim (new bearings etc) but now it judders at low speed (0 - 10mph) if I'm doing anything but a straight line. If i'm turning even slightly then I get a strange noise and quite a harsh vibration. After 10mph its fine and smooth as anything right up to 150+mph (private road honest!).

Also the car seems to start off OK and after a few miles the problem emerges (maybe after 5 or 10 miles). Which makes me suspect the wrong grade of oil maybe? As it gets hotter it thins too much or not enough? Does this sound plausable?

I'll take it back to the garage at some point but haven't had the chance yet and was curious if anyone else has had this??

Cheers chaps!

[d_drinks]

Dan, it could well be an oil issue however I would say not to drive the car while this is the case. You might end up causing heavy/premature wear to the gears within the diff as the lubrication will not be sufficient to prevent this. This could lead to complications with any warrently offered on the rebuild, and lastly it maybe that there is something mechanical wrong with the car again the same problems with wear etc may arise. Not wishing to dampen your parade, but I would get it looked at ASAP by the company that rebuilt the diff. Hope it's sorted soon and your back to happy motoring

[hut49]

Presume you've checked that there's some oil in the diff? I'd be worried by the symptoms you've described and would want to get it sorted before further use (either on public or private roads). I'd also check that the six bolts that attach each drive shaft to the diff housing have been correctly tightened. If the joints are worn then they can be noisy and maybe this has been accentuated by the recond diff. But I'm guessing here so I think the message is to have it checked by someone in the know.

[GreenV8S]

My LSD juddered when turning at very low when it was brand new, this went away when the car had done a few hundred miles. I think was just from a combination of stiction in the friction plates and a small amount of flexibility in the half shafts etc. If you get any play, vibration or heat build-up I would take the car off the road. Otherwise I'd continue with the running in procedure. (You *are* running the diff in, aren't you?)

[dannyboyo]

GreenV8S said: (You *are* running the diff in, aren't you?)

Yep! I've probably done about 800 miles since i got the car back. Took it reasonably easy for the first 500!!

It's a bit awkward not using the car till i get it sorted! Working everyday till friday night then got to go to Wales Fri evening! God, i need a second car!!

One thing I will add (if it helps!) is, it's quite a fast vibration, even if the car is crawling along as slow as possible. Sometimes accompanied with a low pitched humming noise! And it only happens when there is power applied (even a small ammount) and doesn't do it on full lock or in a straight line. Just maybe less than quarter of a steering wheel turn.

[dannyboyo]

Just an update....

I took the car to Top Cats earlier today, drove Brian round a bit, and he reckons it's the wrong grade oil in the diff to. Gonna try and get it changed tomorrow, I'll let you all know! Be hell of a relief if thats all it is! I can finally start pampering my Chimaera now instead of paying for repairs!!!