Mobil 1 75W 90 LS

[SouthernAZ]

Has anyone used the Mobil 1 75W 90 LS (for limited slip) for their differentials? If so, what is your opinion of it? I'm going to change my differential fluids this weekend and that seems to be the best quality I can find. Yes, I know there's certain GM fluid out there but I don't have a local GM dealer.

Thank you....

 

[swathdiver]

The factory fluid has the limited slip additive already in it. Do you have Amazon Prime? What fluid does your front differential take?


https://www.amazon.com/ACDelco-10-4...pID=41VrGILRTML&preST=_SY300_QL70_&dpSrc=srch

 

[roosh725]

I replaced mine with Mobil 1, no issues.


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[SouthernAZ]

I guess my main question was how much difference does the "Limited Slip" part of the oil matters. The Mobil 1 says specifically "LS" for limited slip rear axles but the GM part number oil doesn't say that. That's why I was wondering if anyone has used the Mobil 1 with the "LS" designation and had any ill effects. I had read on some other forums that limited slip type gear oil may lead to chattering on G80 rear axles but I can't figure out if that's what we have on the Suburban/Yukon XLs with the 3.42. I may try the Amazon route as swath diver suggested. Or maybe just go with the Mobil 1 as roosh725 suggested....... Hmmmm decisions decisions

 

[HiHoeSilver]

I guess my main question was how much difference does the "Limited Slip" part of the oil matters. The Mobil 1 says specifically "LS" for limited slip rear axles but the GM part number oil doesn't say that. That's why I was wondering if anyone has used the Mobil 1 with the "LS" designation and had any ill effects. I had read on some other forums that limited slip type gear oil may lead to chattering on G80 rear axles but I can't figure out if that's what we have on the Suburban/Yukon XLs with the 3.42. I may try the Amazon route as swath diver suggested. Or maybe just go with the Mobil 1 as roosh725 suggested....... Hmmmm decisions decisions

Look in your glove box for RPO code G80.

 

[swathdiver]

I guess my main question was how much difference does the "Limited Slip" part of the oil matters. The Mobil 1 says specifically "LS" for limited slip rear axles but the GM part number oil doesn't say that. That's why I was wondering if anyone has used the Mobil 1 with the "LS" designation and had any ill effects. I had read on some other forums that limited slip type gear oil may lead to chattering on G80 rear axles but I can't figure out if that's what we have on the Suburban/Yukon XLs with the 3.42. I may try the Amazon route as swath diver suggested. Or maybe just go with the Mobil 1 as roosh725 suggested....... Hmmmm decisions decisions

David, what year is your truck and what is it? I just peeked inside a 2017 owner's manual and see that they're using different fluids from my generation and the 75W90 you mention is for the front differential and not the rear. The rear on a '17 takes 75W85, PN# 19300457. The transmission for the Denali takes a different fluid Dexron HP compared with the others and transfer case which use Dex VI.

The GM lubricant I posted for is for the 2017s front diff (and GMT900 rears) and does contain the limited slip additive. In the old days, too much or too little would cause chattering. I've had no chattering at all refilling mine with the appropriate amount. Our differentials are a combination, locker and limited-slip. If Mobil's product contains the LS additive, I'm sure it would be fine to use as well. My own preference is for the original.

 

[roosh725]

If you want the best, go with Amsoil. This is one of the best testings done on gear oils, give it a read. I’ll be changing to Amsoil next time around.

http://www.lastgreatroadtrip.com/wp-content/uploads/2010/11/gear-oil-comparison.pdf


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[sumo]

Amsoil all the way

 

[SouthernAZ]

David, what year is your truck and what is it? I just peeked inside a 2017 owner's manual and see that they're using different fluids from my generation and the 75W90 you mention is for the front differential and not the rear. The rear on a '17 takes 75W85, PN# 19300457. The transmission for the Denali takes a different fluid Dexron HP compared with the others and transfer case which use Dex VI.

The GM lubricant I posted for is for the 2017s front diff (and GMT900 rears) and does contain the limited slip additive. In the old days, too much or too little would cause chattering. I've had no chattering at all refilling mine with the appropriate amount. Our differentials are a combination, locker and limited-slip. If Mobil's product contains the LS additive, I'm sure it would be fine to use as well. My own preference is for the original.

I called a few dealerships and they all had different answers to some degree. We do have a version of the G80 rears on most Yukons/Tahoe/Suburbans. They did mention the new 75W85 oil. Apparently GM is now recommending it for 2015s on up, the catch is that it's hard to find in the aftermarket, but they'll be happy to sell it to you for about $25 a quart. Makes you wonder if it's more of a marketing ploy. Anyyyyways, I went ahead with the Mobil 1 and so far no issues.

Thanks All!

 

[Mighty Hd]

You’ll be fine with m1. Been in my z71 for 60k