Just changed the oil in my diffs at 60,000 mile change. The oil came out looking like the day I put it in 30,000-31,000 miles before.

I have towed 10,000 lbs of 5th wheel probably 10,000 miles of that 30,000. As I said the oil looked new, the gears looked fine and there was virtually nothing on the drain plug magnets.

I changed the oil originally at about 13,000 miles and then again about 30,000 miles. I decided to run it to 60,000 miles to see how it looked. This change just about finished the 5 gallon bucket of gear oil that I paid about $110 for in 2005. I just bought another bucket to make sure I had enough and I paid $185 for that one, same brand, same viscosity, and same store.

Why does Dodge say change the diffs at 15,000 miles if the oil is still good at 30,000+ miles even when towing? I understand that the engine oil needs changed more frequently due to soot and other contaminants loading the oil but why the diffs?

 

Some guys don't change it for 100,000+ miles, and some just let it go.

I guess it saves their butt...

I had 10 year old diff fluid in mine when I changed it - very little shavings and the oil looked great.

I dunno.

 

Looking great and working great are two differnet things. With nothing from the outside getting in, the oils not really going to change color. It can, however, break down and become less lubricating.

It'd be interesting to see if anyone has sent it off to a lab after 30k or 60k or 100k with no changes, whatever the case maybe, just to see if it is still good or not.

Im sure someone here has to have done that... i'll wait and see!

 

I've found that the oil often looks filthy at the first service interval, or even before. I blame it on break-in. After that, it seems to stay clean longer.

 

I changed all my vehicles every 30K. my trooper was black at 30K on the rear, but the front looked good.

I haven't really researched the subject, but the primary killer of oil is contamination, not wear.

 

Thanks guys, I noticed there are several other threads on diff oil and a lot of people saying that they just run it 50,000 to 100,000. I don't want to buy a new rear end or front for that matter so I guess I'll try 40,000 and see what happens.