My 99 4x4 Jimmy just rolled over to 80K miles soI want to changefront & reargear lubes.
It gets perdy darn cold around here, like below zero.
I have a couple quarts of "Mobil1, 75W-140 SuperSyn Anti-WearTechnology,LS Synthetic Gear Lubricant, Light Truck & SUV Formula"Thats a looong name but what does all that mean? 'SuperSyn'? LS?
Whats the differance between Mobil1 75W-140 and the regular Mobil1 75W-90?
What is the application of the 75-140?
The tuffest use my Jimmy will ever see, maybe, will be all day interstatedrivesup to75 mph with a load not more than what it was designed for in blistering heat and/or frigid cold.
The 75W-140 sounds like it would be better suited for hot weather use as opposed to 75W-90.
I already have the 75-140 but I can exchange for 75-90.
Any info would be appreciated.

Thanks Much
Angelo in northern Illinois

 

Not the 75W140 for the rear axle. If you want to use Mobil, I say either thisor this. Take your pick.

 

Going with a 75w140 will reduce your mileage. You definitely want to go with the 80w90 or synthetic 75w90. I would go with synthetic 75w90.

 

Yeah, thanks guys. I figure that if I lived in Arizona or New Mexico a little heavier lube may apply.
I'm going to use Mobil1 75W-90 for front and rear differentials and Automatic TC Fluid GM pn 12378396 for my Auto 4x4. Right?
Is the GM parts dept. the only place to get ATC fluid or can it or equivalent be had under another name elsewhere?
How much can I expect to pay per qt. of ATC fluid pn12378396?

Angelo

 

I would only get the Autotrac 2 fluid (do not just go by that PN as it may have changed). Yes, the parts department at your dealer is the only place to get it. The last I purchased was around $7 per quart if I remember correctly. I have to get some more to do the transfer case in my Rainier.

 

Autotrac II, Thanks for the exact name. I'll ask for it.