What a bunch of jerks! You can't go wrong with any of the brand name synthetics, i.e., Shaeffers, Amsoil, Mobil 1, Valvoline, Royal Purple, etc. I put in Royal Purple 75w-90 two weeks ago, mpg went up 2 mpg. Definitely, find another dealer!

 

Here ya go. http://www.genosgarage.com/prodinfo....mber=MH-AA11.5

 

When I installed the Mag-Hytec rear differential cover, went to Wally World and got the store brand gear oil. Full synthetic, 75 - 140. Plus went to Auto Zone and got the store brand additive. It took 7 qt. gear oil at $9.28 each and 2, 8oz. of additive at $4.29 each. I didn't use the big brand name products. I would bet that the Wally World Full Synthetic gear oil is just as good as the gear oil the Dealer sells.

 

Well..........if you study a little chemistry and you'll find that statement isn't quite true.

There is a couple ways to make PAO base stocks. But in the end it is still hydrocarbon based just like "dino" oil.

 

I'm going to change out the diff this weekend.

It stated I had a locker differential and not a limited slip. The difference is the limited slip has clutches therefore the additive.


Window sticker states:

Axle Rear 11.50
Axle Anti-Spin Differential.

Engine 5.9l HO Cummins Turbo Diesel

 

The 11.5 AAM axle is a gear type differential.

It is not a locker and it doesn't have clutches

 

Well I read my maintenance manual.

Schedule "A" stated changing it at 100,000 miles.
Schedule "B" stated changing at 15k intervals.

So I guess at 50k I'm probably ok.

I changed the diff fluid, no unusual wear, not dirty, not foamed up. I almost took a picture of how purty it was....I took a flashlight and shined it up pass the pinion gear(small gear name?) and it looked very clean. Stuck a magnet in the oil resovoir and got minute dust particles that were metallic. But not enough o cause any alarm.

I put in RP 75w140 and measured out 120 oz as to the refill so I didn't over fill.

I want to say thanks to all on this forum for being a good source of reference for anything to do with these beasts.

Also, I couldn't get my AC problem to reoccur...yet.....


Thanks again and again. Next I tackle the atf4+ transmission fluid change and engine oil change.