Had a buddy's diff fail on him...

[AmishFury]

Originally Posted By: Zaedock
No point in doing a diff "flush". Save your $ on the motor oil and buy a tube of RTV. Pull the cover for inspection and replace with a few quarts of Supertech 80W90.


or 75w140 if you have tow prep or tow package (you have 3.73 gears instead of 3.55)

seriously first chance you get break out the tools and pop off the diff cover if you want to change the fluid

 

[Lyman]

Pull the cover off and clean it out real good. RVT is all you need going back together. You can get a good idea of the shape of your rear gear this way.

 

[gomes512]

Depending on the mileage I'd also go ahead and pull the shafts out a bit since you got the cover off. Good way to check if the bearings are starting to eat the shafts or not. I've saved a couple from premature deaths that way by changing the bearings (the shafts aren't cheap to replace).

Just a few extra steps, tires, calipers and the cross pin lock bolt.

 

[metalboy]

No oil will save you from an overload failure.

 

[SOHCman]

You can do a "flush" but only use actual gear oil. It will clean out junk just fine. No diesel, no motor oil. Those would probably cause the harm you are trying to prevent.
I flushed both my trucks diffs when I first got them because I was unsure of the maintenance history.

At first I hated my 250 not having a drain plug like my Toyota, but then after popping the cover off and being able to wipe out the crud from the corners plus inspect the gears for wear I have come to appreciate it.