Rear Differential Fluids

[Dawg]

I am going to change out my OE rear cover and go with Mag Hytech. The truck is used primarily for towing. I figure a little extra fluid won't hurt. Last time I changed my fluid I used the GM stuff. I was thinking about tracking down some Mobil 1 this time. Any opinions? Any other suggestions?

Thanks.

[DmaxMaverick]

Mobil 1 is good stuff. I use Amsoil, but know of a lot of folks using Mobil 1 without issues. It would be my first choice, if Amsoil weren't available when I need a change. You'll need 75w-90 for normal use, or 75w-140 for extreme use (hot climate, frequent very heavy towing, etc.).

[Heartbeat Hauler]

Mobil 1 is good stuff. I use Amsoil, but know of a lot of folks using Mobil 1 without issues. It would be my first choice, if Amsoil weren't available when I need a change. You'll need 75w-90 for normal use, or 75w-140 for extreme use (hot climate, frequent very heavy towing, etc.).
x2 on this!

But, purty much any synthetic that meets the GM spec will work. I too am running the Amsoil 75w-90 and it's pricey when you include shipping.

I'm thinking next go round I'm gonna try the synthetic Super Tech 75w-90 that Wal-Mart sells it is waaaay cheaper and it meets the GM spec. If you are cost conscious and wanna save a few bucks this might be the way to go.

[Dawg]

Thanks for the input. If I can find it around here, I am going to try for the Mobil1. If I can't get the M1 without a bunch of running around, I'll go for something else that meets spec. Thanks again.

[Heartbeat Hauler]

Thanks for the input. If I can find it around here, I am going to try for the Mobil1. If I can't get the M1 without a bunch of running around, I'll go for something else that meets spec. Thanks again.
Mobil 1 synthetic is top shelf stuff, can't really go wrong with that! When I did mine this past fall I couldn't find enough of the Mobil 1 syn at any given time to go that route. Same goes for the Valvoline synthetic, so I just ordered 6 qts of Amsoil. Like I said though I may try the Super Tech synthetic at Wally World...it's ALWAYS available. :D

[Mark Rinker]

I have gone with Amsoil, Mobil, and GM synthetics...but the one thing I never do with all the heavy towing miles is let it get past 50K miles.

Never.