I just purchased 10 quarts of Amsoil 75w-90 syn gear lube. They also had a 75w-140 syn gear lube, this was also $3 more expensive then what i bought. What is the difference between the two? She i go with the 75w-140? The guy at Napa could not tell me. I do not believe that i have a LSD diff, so i wont be adding in any friction additive, is this the right move? Thanks for the help

 

If you tow heavy or live where it is hot (or both), 75W-140 is recommended.
That being said, it is hot down here, but I have been too lazy to change mine out from the 75W-90

~Rob

 

Thanks, it is only hot maybe 3 months out of the year at most up here and i dont tow anything at all, just a snowmobile trailer. So it sounds like what i got will suit me right. Thanks again

 

Yes. Don't need friction modifier with amsoil... already included. Won't do any harm if you don't have LSD.
Take your VIN # to a dealer and ask for a 'build sheet', if you are not sure. Will tell you all options on your truck...from the factory. Should be free and nice to have if you bgt used.

75w-90 is just right for Me. weather, no heavy towing. I've been up there in the summer and my diff. gauge never got over 140*. Down here, a normal summer day starts at 160* and climbs from there based on speed & load.
Difference is a 75w-140 will be thicker at operating temps.

RJ

 

Thanks for the info RJ, that is just what i needed to know

 

I got my covers put on this afternoon, they look awesome!! Putting them on was so simple. For the front, i did have to drop the tie rod on the drivers side, but that was the only thing i needed to do. I really like the dipstick feature. My dad liked them so much, he is ordering up a set for his truck on Monday, hes got a Dana 80 and a Dana 60. Thanks again for the helpful information.

 

Got pics.....?

 

Speed shops usually have a selection of high end gear oils.

I'm a Redline guy myself.

 

I pulled the Mag-Hytec instal recommendations from recycling trash (for AA 14-11.5 diff cover).

Oil level dipstick should be tightened to 30 in. lbs.
Drain plug also 30 in. lbs.
Allen cap screws for the cover itself: 12-16 ft. lbs, in a "cross tight" pattern.

By the way, I originally tightened the Allen cap screws by mistake to 30 in. lbs, and there was no oil leak even then.