Rear end fluid change. Limited slip additive ?'s

**RPO_WU8** · 09-24-2009, 10:12 AM

I did a rear end fluid change on my 2000 SS which now has 58K on it. I hadn't done one in about 35K miles and the fluid looked just fine. I put in what I always put in mobile 1 75/90. used a new gasket yadda yadda yadda but my real question is GM additive 89021958 is what was sold to me at the dealership when I asked for limited slip additive. This crap was like $19! and it looked different then what i used last time which I think was part # 1052358. The guy at the counter said that this was the new part number and it replaced the old one. Anways I dumped it all in (I think 4 ounces) and now I am reading that is a concentrate and you are only supposed to use like 1 ounce or something like that and its for a GTO or something. I have not drove it more than maybe 2 miles and everything sounded ok but whats the story here. Did I screw up and use the wrong stuff? Is the guy from the GM dealership full of crap? I am going to have problems? Doing this kind of work is a PITA cause I live in a apartment and I do not want to change out new fluid but if I need to I will. This did not look like the usual whale sperm lol that I had been getting from GM but instead it looks like a green dye of some kind and it seems pretty runny and not thick. Any thoughts?
Thanks,

**Hi-Po** · 09-24-2009, 12:21 PM

It is very expensive stuff buying it from the dealership. Your supposed to put all of it in. Chinazone has it cheaper. Your fine

**Poppn** · 09-24-2009, 04:14 PM

As far as I know, the 99 and up cars have a Torsen differential which doesn't require an additive, but it doesn't hurt to add it.

This is straight from install university:

You need to fill the rear differential with the fluid. The housing will take approximately (two) 2 quarts of fluid. As we stated at the top of the install document we used the GM additive but there is no need to do this in a Torsen unit.