Aam 11.5 diff. Oil

[DaveHess]

Steved: Didn't think about the noise issue being in the lighter oil. There's a thought. I want to put a Mag-Hytec on the rear its just coming up with the coin for that piece that is killing me. I haven't decided if I'll maintain the 15K fluid swap outs with the new cover or double it to 30K since there is so much fluid in there. Seems to be a fitment issue with the front covers that I don't want to deal with.

 

[steved]

SI want to put a Mag-Hytec on the rear its just coming up with the coin for that piece that is killing me. I haven't decided if I'll maintain the 15K fluid swap outs with the new cover or double it to 30K since there is so much fluid in there. Seems to be a fitment issue with the front covers that I don't want to deal with.

Ebay... I bought an ORU (Off Road Unlimited) polished and finned aluminum cover for $50 shipped a while back... while its not a Mag-Hytec, it serves the same purpose. I never had to deal with the front because it doesn't turn because of the DT hub kit. I look at the fact the cover is a bolt on part underneath the truck that only the guys with the subcompacts ever see while you're driving down the road...



I have 120k on Royal Purple 85w140 (almost 9 quarts of it) and it looks like the day I put it in use... I don't buy the 15k intervals, mainly because there is little to no difference in these differentials and the Dana they replaced. Add to the fact there are 10. 5AAMs that have been in use since the 70s with little to no maintenance (and they still live), I just can't see a 15k change interval.



It would also be different if I pulled into the driveway, popped the plug, and it was cloudy (read: contaminated); but its perfectly clear, with no obvious signs of degradation. I might consider more frequent changes if that was the case, but to date it hasn't been... 206k on the clock with 4. 10s (more pinion RPM than a 3. 73). Gear oil is pretty stout stuff.

 

[AH64ID]

75-140 is recommended for HD use.

Actually its not recommenced for any of the AAM HD axles, by Dodge nor AAM. I have called to and spoken with AAM about their 11. 5" axle. That axle and gears were designed to operate on 75w-90 under 99% of operating conditions. The engineer told me that unless you tow well above GCWR thru Death Valley in the summer that there is no benefit to 75w-140, infact it will detract from your mileage.

I run Amsoil 75w-90 and a Mag-Hytec diff cover. If I felt that it wasn't enough i would run the Amsoil 75w-110... but based on what AAM told me I will continue to run 75w-90.

 

[steved]

The engineer told me that unless you tow well above GCWR thru Death Valley in the summer that there is no benefit to 75w-140, infact it will detract from your mileage.

Even my 85w140 didn't drop my mileage... I posted some of the best mileage numbers with it in fact.



Low 20s with 4. 10s is nothing to laugh at.