OK last year i changed my rear end fluid, i used valvoline syntec oil, its synthetic, of course, and it says "for limited slip rear ends" or something, which lead me to believe i dont need that limited slip additive made by GM, but i have no idea, do i still need to put this additive in there even though this oil says its for limited slip rear ends? sorry im just confused

 

Put the GM limited slip additive in anyway. I ran into same situation and my rear end would act up. Put in additive and rear has been fine ever since.

 

From my experience....Your rear end will let you know if it does not like the fluid you have in there. I used some Mobil One Synthetic in mine with the Additive and it was fine for awhile then it would start clunking and binding. I replaced it with the suggested GM gear lube and GM Additive and it has been very happy ever since.

 

Binding you say???

Mine feels likes its binding and clunking, changed with mobil one and gm additive not to long ago, was doing it here and there a little after the change but its gettin worse and worse now...

What did it feel like for you? Very curious here, Would like to save my rear end if i can...

 

Should I go ahead and change the fluid ???

Its cheap enough to and easy with the T/A Girdle....

I rather not rebuild this rear unless, I NEED TO !!!

 

Mine would mostly do it in reverse when I was backing into my garage...It was a loud clunking noise with some hesitation, literally felt like the rear-end was going to fall out of the car. I figured my rear end was a gonner....but with only 30k on the car, that seemed odd.

As usual I logged onto this site and a couple of people told me to change the fluid. I changed the fluid to the Mobil One and the GM additive, which helped immediately, but it wasn't long before it was back again and worse.

I also had a leaky pinion seal, so I took it to a good shop and had them tear into the rear end, fix the pinion seal and inspect the condition of the posi. Everything looked fine.....they replaced the fluid with GM fluid...the guy there highly recommended using the GM fluid with the GM additive (Keep in mind this wasn't a GM dealership either) I took his advice and all seems good. I could actually feel the difference.

I highly suggest changing the fluid...and make sure you drop the pan and not just suck it out through the vent plug.

Aaron

 

did you have any metal in the oil ??

 

The first time I changed it, I did not see any metal (at least visible)in the gear lube. It wouldn't seem odd to me that you might find some powdered or tiny metal shavings.

The second time mine was changed, I didn't do it so I am not sure what they found. They just told me everything looked good.

Aaron