[oneredry]

coming upon t 1500 magic number mark and I want to be crystal clear. I seen other threads talk about this but the more I rifle through them they seem to be not concrete in information. So:

my owners manual (car picked up on 3/15) states that I need GM part number 88862624.
my dealer whom I trust and gave my vin to, gave me the similar part number but with an LS additive. which doesn't make sense because if this GM part number has the LS fluid already built into it, why would I have an extra tiny bottle for me to add?? ok so I'll question that later.
Now, on here, some of you are saying that the Part number has changed (and had a page added to the owners manual to reflect this) to the regular GM axle fluid but to add the modifier. can someone please identify what should be exactly?

Thanks with sugar on top!

[Wesley40cal]

2016 publication:
GM#
88900401
AddLimitedSlipAdditive
88900330

Ls gear fluid 88862624 in october 2015 publication seems to hold up but dealer knows more. Right?

[BradfordCamaro]

This is something I want to know to.
Why the changes? Do we go with the fluid only....or go with the updated fluid and L/S additive?

[oneredry]

my thoughts as well.

[Mountain]

My take on this is that the 88862624, although has friction modifier in it, doesn't have enough to quell customer complaints about the differential clutches being noisey on tight turns. I think GM switched service to the non-friction modifier inclusive fluid, 88900401, and to add friction modifier separately to alleviate customer concerns. Just my take.

Both are 75w-90. Both are "synthetic".

[JFM-jr]

Do we add the entire bottle of additive and add gear oil until fuilled to proper level? Im looking to do this too.

[citizennick]

I just bought Royal Purple Max Gear 75w90 and then I saw this thread. I assume some members are running the same fluid since it is fairly popular?

[oneredry]

if you log into "mychevy.com" there is a section or phone number that states questions regarding your vehicle. I guess I'll call and test their knowledge. Stand by..

[JFM-jr]

interested to hear this info you get

[oneredry]

When I called GM I explained that some people were getting leaflets added as a add on to there owners manual, explaining that the Part number to the diff fluid has changed to the above mentioned. Howerver, when I further explained that my original owners manual says one thing, my dealer giving me another, and some of you give information about a "added leaflet to the owners manual explaining yet another" which led to the investigation.
The person I spoke with talked with one of the engineers (while I was on hold for 10 minutes) stating that this is the case and can see how the confusion was. So instead of giving the wrong information they took it to the next steps and went further with it. After a few hours, I received a phone call from one of the actual engineers. They told me per my VIN, the correct part number is 88862624.

So I further asked the engineer, does it really matter (were talking SS here only) is there a real difference with these fluids? I mean I was under the impression that all SS had the G80 rear end. He didnt' elaborate, and could legally only say this is what is tied in with your VIN.

There you have it.. heard it from the horses mouth.

[gahammerle]

Originally Posted by oneredry

I mean I was under the impression that all SS had the G80 rear end.

All SS and the manual V6 & I4 have the G80.

[mbar]

Originally Posted by oneredry

The person I spoke with talked with one of the engineers (while I was on hold for 10 minutes) stating that this is the case and can see how the confusion was. So instead of giving the wrong information they took it to the next steps and went further with it. After a few hours, I received a phone call from one of the actual engineers. They told me per my VIN, the correct part number is 88862624.

So....with or without the additive?

[oneredry]

Originally Posted by mbar

So....with or without the additive?

without for sure.

[Mountain]

Originally Posted by mbar

So....with or without the additive?

88862624 already has friction modifier pre-mixed in.