K2 Differential Fluid Change: Limited Slip Additive?

[eppyfish]

Hey guys,

Getting ready to drain front and rear differentials and replace with Mobil 1 75w90 synthetic (will be my first go at differential fluid swap, but looks easy). I've noticed discussion on a few forums about LS additives and also a version of the M1 gear oil that has LS additive in it already. Do I need this in my 2014 Sierra? I don't want to wind up with the clunking and shutter that's described on some vehicles when they don't use the LS additive. I planned on using the same oil in the front and rear diff.

 

Thanks

[newdude]

NO additive. GM uses 75w85 for the rear differential not 75w90. Front is 75w90.

[Black02Silverado]

You do not need any LS additive for your rear differential. The Mobil 1 will work just fine. You can use AMSOIL's Severe Gear 75w-90 as well for both front and rear differentials.

[eppyfish]

You do not need any LS additive for your rear differential. The Mobil 1 will work just fine. You can use AMSOIL's Severe Gear 75w-90 as well for both front and rear differentials.

The Mobile 1 seems to say it has LS additive in it. I can't find the Mobil Delvac locally, which doesn' t have the additive. I'm trying to find something local so that I can make do the job tonight. I'd go with the amsoil, but it wouldn't be delivered before i have to go drive and put several hundred more miles on my truck.

[sdeeter19555]

Mobil 1 is fine, you don't need or want to add any LS additive. Most synthetic are LS rated without additives by their nature.

 

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[eppyfish]

https://shop.advanceautoparts.com/p/carquest-grease-and-lube-75w-90-gear-oil-685-32/7070381-p?c3apidt=22909218643&gclid=Cj0KCQjwqvvLBRDIARIsAMYuvBH0D6CA1YJAECjWbELDdEtumC9gnES3hEgW3v85NVUTOfHCUU0ViDsaAqtcEALw_wcB&gclsrc=aw.ds#fragment-3

 

 

This is available local to me and they have 5 qts in stock local to me. Carquest branded, produced by Old World Industries. Its a fully synthetic, meets GL-5, no additives. Thoughts?

[eppyfish]

Mobil 1 is fine, you don't need or want to add any LS additive. Most synthetic are LS rated without additives by their nature.

 

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So this product linked here is what I'm looking at in the local stores.

 

https://shop.advanceautoparts.com/p/mobil1-synthetic-gear-lubricant-ls-75w-90-1-qt.-104361-98w573/7070039-P?searchTerm=75w90

[sdeeter19555]

So this product linked here is what I'm looking at in the local stores.

 

https://shop.advanceautoparts.com/p/mobil1-synthetic-gear-lubricant-ls-75w-90-1-qt.-104361-98w573/7070039-P?searchTerm=75w90

That's what I used for one fill, then I happened onto five gallons of Amsoil 75w140 (for $50), which I currently use. I didn't have any issues with the M1 with my G80 while I used it.

 

I still have ten quarts of M1 in the basement for the car, which I will change when it hits 10k.

 

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[MrNasty]

I found Mobil Delvac at a service center for semi's. It was even cheaper than ordering from Amazon. Could try there.

[eppyfish]

I found Mobil Delvac at a service center for semi's. It was even cheaper than ordering from Amazon. Could try there.

Any chance you recall the service center name? I guess it'd only matter to me if it was a national chain.

Thanks

[Black02Silverado]

The Mobile 1 seems to say it has LS additive in it. I can't find the Mobil Delvac locally, which doesn' t have the additive. I'm trying to find something local so that I can make do the job tonight. I'd go with the amsoil, but it wouldn't be delivered before i have to go drive and put several hundred more miles on my truck.

Depends on where you live as to how fast it would be delivered. What is your zip code?

[MrNasty]

Any chance you recall the service center name? I guess it'd only matter to me if it was a national chain.

Thanks

It was a local service center. I think Peterbilt carried but they were out. I got enough for mine and the wife's for less than ordering just enough for mine alone.