My 04 XLR has a rear end clunk when backing up. Any suggestions. Mad Dog

Welcome to the XLR Forum.

There is some information posted on this issue in the Technical Section.

What you need to do is to change the rear end fluid and add a positraction additive. This process may take more than one visit to the dealer but usually fixes the issue.
Your positraction plates are sticking so by changing the fluid they are relubricated with the additive and the new fluid and will not stick. The newest issue on this is that sometimes the GM fluid will do the tirck and Cadillac has started using Mobil 1 Positraction Fluid as an alternative.

Please let us know how it workd out for you.

Regards

WOW what a web site. I'll give it a try and let you know. Many thanks. mikebev

I had the same scenario ( clunking noise when in reverse) on my 2004. This was solved by changing to the Mobil 1 Positraction fluid. No further problems.

LWM

I had the same issue on my 04 as well.
Fluid change got rid of it.

FWIW, there is a TSB out on that problem:

TSB No.: 070420002 NHTSA No.: 10022263 TSB Date: January 1, 2008 Date Added to File: July 24, 2007
Failing Component: Power Train, Driveline, Differential Unit
Summary: Rear axle clunk and/or chatter type noise on turns (drain/refill rear differential fluid). Updated 4/11/08.

TSB No.: 3559 NHTSA No.: 10016945 TSB Date: January 1, 1901 Date Added to File: October 18, 2005
Failing Component: Power Train Axle Assembly
Summary: Rear axle chatter shudder on turns. Updated.

Thanks guys. The baby goes in Fri!! Mad Dog

Mike:

Please be sure to let us know how it comes out. That way we will have a good member experience level on the permanent resolutions to these issues for others to reference.

Regards

backed it up this am. NO NOISE!! Mobile 1 did the trick. Thanks everybody who replied. By the way, how long did your first set of run-flats last on your 2004. Mine were shot when I bought the car with 4900 miles????? dealer put on the same tire with non run-flats and I am now at 23000 with little sign of wear, and I do push the car.

Mike:

Congratulations on the Rear End fix (for your XLR) Ha, Ha!!!
If it starts making noise again just go get the fluid changed and then go from there.

My experience and driving habits used up a set around 20-22k.
As you may already know the compond on the run flats is softer....for the ride.

Also it is interesting that the pressure for these tires is now 30lbs hot. It was 32 hot.

I am very happy with my new set and think that Michelin made a good tire here. You may already know that XLR moved over to the Goodyear products in.....2007 I think.

Regards