Hello all. I have an '83 Olds 98 Regency Brougham that after driving for a while the rear end binds during low speed turning. From what I know, Lsd/posi cars will do that when the diff fluid has gotten old or there is no or not enough friction additive in there. The problem is that I have no idea what rear end I have. No rpo sticker, apperently they became the norm for '84 on. Can someone please decode my vin because all of the online lookup produce a basic vin decode or nothing.

Thanx in advance.

 

Sorry, I forgot to add my vin:

1G3AW69Y5DM785130

Thanx again.

 

There is no information in the VIN that will tell you anything about the rear axle.

 

I had a 1983 Ninety Eight Regency Brougham that developed this exact same issue. IIRC there wasn't a tag on the diff either. Lift the entire back end of the car and spin the tires. If they both spin the same direction you have limited slip. Just based on your description of the problem, you have LS though.

Change out the fluid (I'd use conventional 80/90) and a bottle of additive. Put the additive in about 1/2 way through the fluid change. The problem should go away right away.