the GM 8902177 is a discontinued part according to gmpartsdirect.com. I would go with the 88900401.

http://www.gmpartsdirect.com/oe-gm/89021677

 

the GM 8902177 is a discontinued part according to gmpartsdirect.com. I would go with the 88900401.

http://www.gmpartsdirect.com/oe-gm/89021677

Thanks for the response esox07. I was thinking that as well but see that the 89021677 is still available on EBay, that's why I was wanting to confirm...

-John

 

Go with any 75w-90 synthetic without limited slip additives.

 

Yah, the ebay sellers are likely just selling old stock. They probably came across a bunch of it in a "going out of business" sale or something like that.
But I would consider some of the aftermarket brands as well as the GM stuff. Mobil, Valvoline, Amsoil, Royal Purple all make great synthetic 75W90 gear lubs that would work great for your truck. They are probably more readily available and less expensive as well.
I am running Mobil in my rear and front diff.

 

Yah, the ebay sellers are likely just selling old stock. They probably came across a bunch of it in a "going out of business" sale or something like that.
But I would consider some of the aftermarket brands as well as the GM stuff. Mobil, Valvoline, Amsoil, Royal Purple all make great synthetic 75W90 gear lubs that would work great for your truck. They are probably more readily available and less expensive as well.
I am running Mobil in my rear and front diff.

Thanks for the advice! I did look at the Mobil1 but that says it has/is for limited slip differentials(75W90 LS synthetic) which would go against what Gozzie posted...??

-John

 

It is "COMPATIBLE" with LS diffs. But as long as you don't add the LS additives, then you are good to go for your G80 differential as well as the front diff on a 4wd. I had that question a little while back.

 

I believe that was sorted out in a different post. I think the Mobil 1 is okay and what most people are saying is don't use the limited slip additives. I know it gets confusing sometimes

 

Thanks for the clarification you guys, I appreciate it!!

-John

 

I will second that a G80 is not a limited slip and should not have any limited slip additive in the fluid.

 

I've been doing a lot of research looking for a synthetic gear oil that dosnt contain ls additives.The oe fluid is great but at nearly $30 a quart it is ridiculous.Ill be running delo syn-gear xdm sae 75w90 when I change mine.Nice part is $5.99 a quart.

 

yeah good luck finding a fluid without LS additive. only things on shelves ...

so tell me... what would all these mechanic shops and dealers use?

 

yeah good luck finding a fluid without LS additive. only things on shelves ...

so tell me... what would all these mechanic shops and dealers use?

The stuff I posted dosnt and it's available at my local autozone.

Dealer will use the oe $30 a bottle stuff
Idependent shop will use whatever from the part store.

 

Would it matter if someone mucked up and put additive in a diff that did not call for it? I`m going to my front and rear and want to know if it needs that additive?

 

I don't know about 2500 series. Check your owners manual.

 

Would it matter if someone mucked up and put additive in a diff that did not call for it? I`m going to my front and rear and want to know if it needs that additive?

For the front diff, which is open, it doesn't matter. But the rear, if it has the G80, it can matter. It may not lock or may chatter.

None of the GM trucks need any additives except the quadrasteer trucks.

 

K thanks I`ll check the build sheet and make sure and add the right stuff. I forgot what I did 50k ago.

 

From everything I have read about the Mobil1 Full Synthetic gear oil I used in my 2500, it has "Some" LS added to it,but if your Diff calls for LS additive that you should add it because there is not enough LS additive to cause any damage. I am running Mobil 1 Full synthetic in my Rear G80 and it works just fine!

Now with that being said, there's not a darn thing wrong with the Delo Synthetic, both are good gear oils!

Matter of fact I changed both front and rear diffs with Mobil 1 Full Syn and drained the transfer case and added Valvoline Full syn.
With heavy rain today I put it in 4 Wheel high and drove 20 miles round trip to the doctor and back without any issues, truck was quiet!! Very pleased!!

 

The use of any additive in locking rear axles (G80) is not recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle life.

 

Would it matter if someone mucked up and put additive in a diff that did not call for it? I`m going to my front and rear and want to know if it needs that additive?

For the front diff, which is open, it doesn't matter. But the rear, if it has the G80, it can matter. It may not lock or may chatter.

None of the GM trucks need any additives except the quadrasteer trucks.

Quadrasteer vehicles use Dana axles and have a different fluid requirement.
It was RPO 86

 

Is there a fully synthetic for the transfer case? I thought there wasen`t but if there is I would deff use it.

 

Use Dexron VI ATF

 

K thanks Mike It would be dextron VI synthetic just to be sure?

 

Sure, you can use synthetic...

 

You want Dexron VI for the tranny and transfer case. You want the 75w90 gear lube for the differentials. Synthetic is a great choice for either.

 

K thanks guys. I have a little project plus a pan drop and filter change for the tranny it`s due also.