Want to make sure Im buying correct gear oil for differentials

[Shtiv]

Got to thinking after picking up order that due to this being AWD, does it need LS (limited slip) gear oil on front? I’m no expert mechanic and not sure if limited slip has anything to do with it being AWD.

 

[Shtiv]

Spoke to a local reputable dealership both the service and parts department, provided them with VIN so they could look up my vehicle and no one knows if it is LS that goes in front. They only know its 80W-90 weight and its capacity. Crazy to me.

 

[Bill 1960]

There is no LSD available for the front, neither OEM or aftermarket. You’re good to go.

 

[Shtiv]

There is no LSD available for the front, neither OEM or aftermarket. You’re good to go.

Thank you for confirming! Based on roughly full day of intense research of reading, calling and watching videos i decided to go with:

Front Diff: Valvoline 80W-90 High-Performance Conventional Gear Oil
Rear Diff: Mobile 1 Synthetic Gear Lubricant LS 75W-90

 

[wjburken]

Thank you for confirming! Based on roughly full day of intense research of reading, calling and watching videos i decided to go with:

Front Diff: Valvoline 80W-90 High-Performance Conventional Gear Oil
Rear Diff: Mobile 1 Synthetic Gear Lubricant LS 75W-90

Good call.

 

[Jason in DLH]

That’s exactly the combo I put in as well (actually I’m letting the rear diff cover bolts bask in penetrating oil as it’s rusted to the max). Already had to drain the front again last night as I broke the axle tube. Went ahead and ordered Amsoil 75W-90 Synthetic Severe Gear. Two quarts cost me $40 after shipping. What was I thinking?

 

[Bill 1960]

Interesting...how much difference was the operating temp between the two?

It’s been a lot of years since I did that testing, but as I recall it was tens of degrees in typical driving, between 90 vs 140W.

There certainly are use cases for heavier oils, typically in heavier vehicles and especially high torque towing. I trust GM to specify lube that is best for the application.

 

[JonnyTahoe]

That’s exactly the combo I put in as well (actually I’m letting the rear diff cover bolts bask in penetrating oil as it’s rusted to the max). Already had to drain the front again last night as I broke the axle tube. Went ahead and ordered Amsoil 75W-90 Synthetic Severe Gear. Two quarts cost me $40 after shipping. What was I thinking?

What did you do that broke the axle tube ?

 

[Jason in DLH]

What did you do that broke the axle tube ?

I think one too many hard starts. Problem is I didn’t feel it happen or hear it (had the bass bumping), so I’ll never know for sure.

 

[LilgDad]

I am not going to deny that GM takes overall fuel efficiency into account when they design the drive train and make fluid viscosity selections. That being said, I have heard of very few people that have had an issue with running the recommended fluids if they use quality products and change the fluids out on a proper schedule. I’m willing to bet that most failures are due to folks not paying attention and letting the fluids go way past the recommended service interval. I would never recommend that folks deviate from recommended viscosity, but would recommend using quality product and doing proper maintenance at recommended intervals. There are a number folks on here that have 200K or 300K on their vehicles that use the “legally required” recommended fluids in their vehicles.

That is me, 200k on my 2011 Yukon Denali XL always used GM spec fluids/parts without issue and she runs like new still ,except for the wandering air ride suspension lol. That I gotta fix still.