Differential Inconsistencies

[KKlepfer]

Most of us are familiar with the ridiculous maintenance schedule for our 11. 5 rear axle. Dodge wants us to change the synthetic oil that they sell for around $18 a quart every 15k.



So I asked a friend/coworker, who happens to own an 03 Duramax that also has an American Axle 11. 5 rear end, what the maintenance schedule GM recommends. His book only mentions a synthetic is required and it needs to be checked and topped off at a designated milage, but does not mention a milage in which it needs to be changed.



Talk about two extreme recommendations. How can the same axle have such a different maintenance schedule? Does anybody know what the politics is on these two different policies.

 

[BHolm]

Have your friend re-check his manual. That might be the schedule when no towing is done but having owned two d-max trucks I know there is a change interval for them. I am pretty sure it is much longer than the Dodge reccomendation though. Probably because our engines actually produce torque and get used for real work. The GM trucks are glorified cars.



I have been changing the fluid early (2500-5000 miles) and using Amsoil severe gear in my diffs. The plan is to change them every 50k. My dually had a change at 5k and at 50k and shorty will get to 100k and another change. That truck tows heavy everyday and I have had no problems. My '01 d-max was on the same schedule and went 97k without and rear end issues. My '99 Ford with a Sterling 11. 5 being worked and maintained similarly needed a rebuild at 100k. I think we have a pretty sturdy axle. Now with only 3/36 coverage on my '06 I could care less what the manual says. It will never fail within the warranty period so I accept that I am my own warranty staition on that part.

 

[Bertram65]

The Dodge has a different type of anti-spin as well which may require the more frequent oil changes. It is a pain doing it with the stock cover, as it has no drain plug. I switched to an aftermarket cover with a drain plug, takes about 20 minutes to change it and cost about about $35 for the Mobil 1. I change the front avery other time, though it is turing all the time it is probably only under power about 5% of the time.

 

[KKlepfer]

Bertram, I have an open diff (no limited slip) and the book still calls for 15k change. It doesn't have anything to do with the limited slip. I agree with BHolm; I'm going to keep changing with Amsoil every 50k. I don't even pull that much. I did an initial change at 5k and now one at 51k. The oil looked great.