I got a good question about a rear-end...

I had my rear-end service at the dealer for it 30,000 check up and they told me I needed it changed. Well I did it. Now I'm up to 37,000 miles and now the gear oil is almost black again!

Why is the gear oil getting black so fast?

There is very little metalics on ther magnet...

Doesn't leak oil or have water in it...

2002 Dodge Cummins Diesel 3/4 Ton - on the scale at 7,800 lbs empty.

 

I don't know why it would get burnt that fast other than you have a problem with the rear end or they didn't service it right. If it were me I would pull the cover and change out the fluid my self. See how long it last and go from there.

 

7,000 miles on rear end fluid is not much and it shouldn't look black after that many miles, first change maybe but not second change or there after. Is it limited slip or open differential? Did the service guy do anything else besides change the fluid?

Water in rearend fluid will cause a milky foamy looking stuff. About the same as water in engine oil.

 

What color was the fluid when new? My synthetic fluid is dark green in color right out of the bottle.

 

What oil did they put into your diff? A few years ago they put the wrong oil in my 94.

 

If you have the LS axle, it may be from the clutches.
Mine quickly gets dark.

 

I'd go back to the dealer. There is no reason your oil should be dark after that short of a time frame on the new lube. Sounds like there is a problem which the dealer should recognize or they blew it somewhere, like didnt change it at all.

 

Well to add to this the pinnon seal was change at that time. I have the invoice showing the seal, cleaner to flush out the pumpkin, and the 80/90 Gear oil.

I guess I will contact them and ask whatz up! I thank you all for the reponse to the message...

 

Sounds like back lash not set properly.