Whenever I turn into a parking spot, I hear a groaning noise that sounds like its coming from the back. It only lasts until I get out of the turn. What could it be? I dropped the LCAs on both sides one time, but I forgot for what. I think it was when I removed the brake calipers to fix the emergency brake issue. Could they be the cause of the noise? Hopefully its not the rear end that is messed up. I havent changed the oil in the time i've had the car (14 months) but it only started making the noise about 4-6 months ago.

Sound like your limited slip rear end and a 10 bolt rear. If you drain a refill the rear and don't use the limited slip additive the rear starts making all kinds of noise. Go to gm dealership and ask for a bottle of it only betweem 7-8 dollars. Then pull the plug on the top of pumkin and drain a little of the old oil out (small siphen hose works well and add the limited slip additive the whole bottle. If its been a while I would pull the rear end cover and completely drain the rear and refill with new oil and the limited slip additive. You will need about 3 bottles of rear end oil to do this. Because of the angle you are working hard to use all the fluid in every bottle. You will be amazed how that little bottle of fluid quiets everything down.

Thanks for the reply. I have never changed the oil, so does the rear end start making noise when it is time to change it? I'll change the oil this weekend and see if it makes any difference.

jaimegmr...does your car shake/vibrate or grind when making this noise?
i have a similar problem but mine vibrates a little. Im also going to change the oil and check to see why its making this noise...

91 RS CONVERTIBLE

No, I dont remember it shaking when the noise occurs.

hey the last reply w/correct oil is right on, also consider that if the rear is still orginal you may be getting ready for new posi-trac and or gears. I restored a 90 R/S and around 160k my rear started the noise as urs when i pulled into a parking space, driveway, as the weight of the car leans the rear end send power to compensate and it binds if u will. it will only get worse until one day it will sound as if a train smaked u in the rear and u will shake or jolt in ur seat. i am restoring a 91 z28 and sure enough at around 140k it started slowly then one day comeing into my drive boom it felt like i was rear ended by a train and the noise!!!! Well towed it to my mech. and it was my positrac...$1400.00 later i had a new posi trac all other gears were ok runs great. hope this helps Bruce

I hope the rear end doesnt need to be replaced. The car only has 95,000 miles. Could the rear end go out so fast? I'm going to change the oil this weekend and see if it stops making the noise. Was the $1400 including labor? or just the part? how much for the part itself?

95,000 miles out of a rear end is not bad at all. I might need a new one again and i average only a few thousand from mine. It all depend on how much power you put down, and how hard you beat on it.

I cant seem to find out how many quarts of oil to put in. I have a Built 10 bolt with 4.11 gears, a SLP posi unit, 92Z28 28 Spline axels and a Jegs Aluminum rear end girdle.
Do I also need GM posi fluid??
How many total Qts should I have in there?
Thanks for the help cause i really dont wanna eff up the new rear.

I think I'm the third (maybe fourth) owner. If it was ever driven hard, it must have been by the original owner. The receipts that I got with the car manual go up to 2002. Car was bought July 6, 1984 with 23 miles. In early 1990, the car had 66,000 miles (about 10,000/year). In Sept 1991, the car had 80,000 miles. In March 1992, the car had 82,500 miles. In Jan. 2002, the car had 86,027 miles. In May 2006, when I bought it, the car had 86,255 miles. Now it has about 95,000 miles. So, the previous owner couldnt have driven it for more than approximately 220 miles from Feb 06-May 06. I dont drive the car hard at all. I've only attempted to burn out once, and I think I failed since Ive never done it before. The car is all stock (as far as I know), except for the exhaust which was installed by the previous owner in Feb. 06. Funny thing is that the car was built in Van Nuys, CA, the original owner lived in West Covina, the owner before me lives in West Covina, and I live one town over in La Puente