OK... brief history... About 9 months ago my 2005 CRD sport started whining from the rear. My dealer was adamant it was a wheel bearing or something similar and kept putting me off, in retrospect, probably so the sound got worse so the could diagnose it more easily. I was convinced it was coming from the rear axel/diff. Anyhoo... it eventually got silly loud and the dealer took it in 2 weeks before the warranty ran out and the rear axel was completely rebuilt. I know the parts for this came to £4,500GBP at cost!!! and these were all internal parts! talk about dealers ripping off manufacturers... It would have been cheaper to ship a complete axle from the factory in the USA to the UK!!

OK... Ever since I got the car back I have had an issue (I didn't take it back as the dealer told me warranty work wasn't warrantied!)

When cold everything is fine and normal. However, when everything gets hot I am getting a strange, very strong vibration/rubbing sound/sensation coming from the rear. This only happens when pulling out from a junction either left or right under load (i.e. foot down in 1st and 2nd.) When pulling a way straight, it's smooth and when cornering NOT under load it is also smooth. I tow a caravan and the effect is very obvious while towing as pulling out of corners under load takes much longer.

The only way I can explain the sound/vibration is that it almost feels like the suspension is compressing and the AT tyres are rubbing really badly on the wheel arches (obviously they aren't). It's so strong that the first time my wife heard/felt it we were towing the van and she thought the rear end was about to explode!!!

A mechanic friend of mine wonders whether the dealer replaced the standard open diff with an LSD (the dealer claims not.) He seems to think my description of the sound/vibration sounds like the loaded rear wheel fighting for traction via the clutch pack in an LSD. Does an LSD make a noise or vibrate strongly when loaded? and why does it only happen when everything is hot (i.e. after a decent run)

Any help or thoughts would be appreciated.

Thanks
Paul

A mechanic friend of mine wonders whether the dealer replaced the standard open diff with an LSD (the dealer claims not.) He seems to think my description of the sound/vibration sounds like the loaded rear wheel fighting for traction via the clutch pack in an LSD. Does an LSD make a noise or vibrate strongly when loaded? and why does it only happen when everything is hot (i.e. after a decent run)

Your mechanic friend is right. An LSD can make groaning and clunking noise (when turning) if the wrong differential fluid is added or the proper friction modifiers are not added. It can tend do it more when it is hot. You can find out if you have an LSD by jacking up one wheel with the transmission in neutral and trying to turn the wheel by hand. The wheel should rotate very freely without LSD and be impossible or very difficult to rotate with LSD. Try both sides so as to maybe detect something else that is the problem.

I have rebuilt a few Chrysler differentials. There is really not much in an open differential to make noise like you describe. When side case gears shafts wear out there can be some clicking or snapping when coming to a straight stop. When the side case gears begin to disintegrate there can be heavy clunking and grinding and can jerk or stop the car when turning. If the side case gears were not properly shimmed I don't know what that would sound like - never done that.

Best advice I can give you is to safely get one or both rear wheels (safely) off the ground and start rotating wheels while feeling and listening. If the noise is coming from the differential, might have to pull the cover to have a look and see what parts fall out.

Jacked up both sides one at a time and both rotate freely! so I don't have an LSD....

Any other thoughts.... Remember this only happens once the axle is nice and warm after a run... could something in there be expanding and then causing issues?

When is the last time you rotated your tires? A tire with a bad belt can give the same noises you are hearing. Rotate your tires and see if the noise moves with the tires. This doesn't hurt to check.

Take it back to the dealer that fixed it!!
Here in the states all repairs are covered 12 months 12000 miles.
Contact chrysler & get them involved.