Towed 7000 lb. trailer from sea level to 4000 ft 6%+ grades, found diff oil all over bottom of truck and on back of truck and trailer when I got where I was going. Best tow speed up hill to keep temps in check was 65-70 @ 2200-2300 RPM's in 3rd. 1150-1250 EGT. Lost 1/2 gal of oil in diff (put in 85-140, what was available) and put it back in to get back. Looks like it came out of the pinion seal. I did not lose any on the way back, and there was no noise from the rear end. Lucky I guess.

Has any one else experienced this symptom?
I'm thinking that the vent could be clogged.

What else should I check for?


Any help would be appreciated.

 

i would check the vent first. you could pull the drivshaft off and check for excessive play in the pinion.

 

If the vent is plugged up, the oil will be pushed out seals, pull the vent out and clean it out, also remove the hose and blow thru that, and finally where the hose hooks to the diff, remove hose and run a pick or small screwdriver thru the nipple into the diff,
just remember, the vent is not the only thing that plugs up

 

Front or rear diff? Front pinion seals are a pain in the rear to get to seal correctly. Go to your dodge $tealer and get the right seals, I couldnt get anything else to work when I did my gear swap. You may also want to check your transfer case tailshaft housing as I know mine leaks right now.

other than that blow out the vents like the others suggested.

 

None of the above would explain this...right?

RJ

 

Yep it would as who know how long(if) the vent was plugged prior to opening the filler plug, and he filled it with higher weight oil, could take longer to heat and build pressure or the higher weight oil may not be able to get past a worn seal yet, so it could be a bad seal as well, but I'll bet on the vent first

 

Well,

I lost the front pinion bearing
I'll pull it apart this week and check the gears and the rest of the bearings.
I haven't rebuilt a diff since 83 and wanted to know if there was any thing special I should know? I plan on doing it in the truck.

Where's the best place to get parts? If the gears are toast I'll probably change them out for 373,379, or 390s any suggestions based on whats in my sig?