At the latest Nor Cal tech day, I decided to change the rear diff oil and transfer case oil. When working on the transfer case, I removed the 10mm upper fill plug first (to make sure I could refill before draining) and a whole bunch of oil came gushing out. That was completely unexpected since the transfer case is specified to take 2 quarts and to fill to the fill hole.

Once it was done flowing out of the fill hole, I drained the rest of it by opening the drain plug (the lower 10mm fill plug).

The oil was blackish but still had a red tint to it and didn't look too too terrible overall. Didn't smell burnt or anything.

By the time I drained both the rear diff and transfer case, I had enough oil to fill 2 Del Vac (engine oil) gallon jugs and another quart bottle about halfway.

This is all on my stock 2002 F250 PSD 4x4 w/ automatic trans. Mileage on the truck is 108k miles. I've owned it for 7 months.

I have no idea how the transfer case could get that filled with oil unless it was filled while off the truck or on its side or at the factory during install or something.. It did not look watery in the least bit so water didn't make it in there.

Any thoughts on how this could have happened?

Has anyone else every experienced this?


I refilled it with 2 quarts of Redline D4 ATF and when I stuck my finger in the fill hole to check the level, I could feel that it was wet and full.

 

From the transmission! Ive seen the rear seal go and overfill the transfer case. You should of seen the lube guys face when it well, got em! He hasn't actually done anything to fix it yet!

 

You should have seen my face when it started pouring out the fill hole. I almost took a bath in it...

I'll check the trans level. Someone mentioned that but I had forgotten. Getting old...

 

Trans oil level was ok.

 

No way to tell how long the transfer case has been overfilled, possibly from the tranny. This could have been going on for a long time for the previous owner who just kept adding fluid to the tranny until it stopped disappearing! He thought "problem healed itself" when in reality the transfer case was plumb full and the fluid from the tranny had nowhere to go so stayed at the full mark. Keep an eye on the tranny level as the problem probably still isn't "healed".

 

I had the trans oil done a few months ago fwiw. I'll keep an eye on it.