GM Limited Slip Differential Additive

[Spooling]

I am planning to do a rear end "gear oil change".

Previously, I used to get everything from GM - namely the rear gear lube + one bottle of "Limited Slip" additive.

Is this additive available from the local Auto Parts Store - in an "aftermarket" brand name?

If I decide to get other-than-GM Lube - I am thinking maybe some "lighter-in-color" Valvoline. I wish to ask the rated viscosity - should it be 80w90?

Many Thanks !!!

 

[lrayzer]

Pretty sure GM still has it, they still build posi cars, Lakewood used to have it also.

 

[rev. 3:11]

Got my posi additive at Advance Auto; right off the shelf; 80w90
HTH!
D

 

[aminga]

A lot of gear oil's already have an additive in it. Plus you only need the additive if you're getting clutch chatter

 

[87-WE2]

When I did mine (on both the GN and my GMC), I went to my GMC dealer's parts counter and when I asked for it and gave him the part #, he looked at me like I was a moron and said he had no clue what I was talking about. I went to O'Reilly and got some from them - it wasn't GM brand, but I figured it was as good as any. I put a half-dose in the GN and had a little chatter, so I put the rest in after the test drive.

 

[m233roller]

Personally I have ran Red Line 75-90 synthetic in my rear end (that use to chatter) for about 19 years and 90 thousand miles with alot of 1/4 passes and ALOT of street driving and have NEVER had one bit of trouble with the rear end. I did have it out about 5-6 years ago and did some upgrades to it and installed new bearings and seals and a new GM posi clutch pack. I know there is alot of pros and cons about synthetic oil being to slippery but it has worked for me for many, many miles. Actually when I had it out the bearings and gears still looked new but I already had all new bearings so I installed them. I have never heard one peep out of my rear end running Red Line and you don't need ANY additive.

 

[turbo nasty]

Synthetics are steered from with clutch type rearends. Eaton for instance recommends NOT using it.

I used to run a bottle of additive and now I run valvoline dino 75w 90 and 1/2 a bottle of lucas with NO additive. Todays oils as mentioned have the additive in it.

If you still have the factory rear end cover get a drain plug kit and slap it in the cover when in therenso you dont have to pull it to drain.

 

[Spooling]

If you still have the factory rear end cover get a drain plug kit and slap it in the cover when in therenso you dont have to pull it to drain.

Whoa man - excellent consept. Wish you would have said something a day earlier. Maybe next time.