differential fluid

I have heard nasty noises whenever I had the wheel cranked over driving around in parking lots, for example. It's a lot louder than the usual noise one hears from the power steering when it's pegged. the dealer told me that someone had put the wrong fluid into the differential. I had to pay for a replacement service....and I KNOW no one has been into that unit. Has anyone heard of the factory putting the wrong oil into the rear differential?

I don't know how it could happen at factory, but do you get your oil changes done somewhere? Dealer? Oil change place where they check fluid levels? Other then dealer, other places (because they may not know) could add something other then required versatrak fluid.

I can say this since I work in a dealership. They lied to you unless you have a rear diff service somewhere else. GM has a known problem with this and the first step is to replace the diff fluid. ZI have replaced several rear diffs on this model. The biggest problem causing this noise ishavinf 4 tires that are not worn even. If you have 2 new tires and 2 used tires the circumfrence difference will bind the rear diff till it explodes. Make sure you change all 4 tires at the same time and rotate them regularly.

I can say this since I work in a dealership. They lied to you unless you have a rear diff service somewhere else. GM has a known problem with this and the first step is to replace the diff fluid. ZI have replaced several rear diffs on this model. The biggest problem causing this noise ishavinf 4 tires that are not worn even. If you have 2 new tires and 2 used tires the circumfrence difference will bind the rear diff till it explodes. Make sure you change all 4 tires at the same time and rotate them regularly.

I did replace all four tires at the same time, so it must be something else. Do you have a reference to a service bulletin or something like that? I opened a case # with Buick Customer Service and would like to pursue this further. I never had anyone service the rear diff....I know, since I would have been charged $200+ for it and I don't forget that sort of thing!

Thanks for your help.

It is a GM problem. They put the wrong diff fluid in at the factory. They should have put a synthetic fluid in but didn't. I saw the Technical Service Bulliten. It says you must drain the fluid. Put in 2 litres of the new fluid ($40 each) let it run through. Put in 2 more and run it for 700 kms. Then do the same thing over again.

I made them do it for free since it was their fault. However, they only drained it once and put 2 litres in. Now the vehicle is a long past it's warranty and the rear end in no good. I will most likely have to get a new rear end. If enough people came forward we could probably get a recall...or a class action.