deuce oil leak - help!

[Jinx]

Moved from this thread...

After driving 100 miles to my destination, I noticed a drip coming from a hole at the bell housing under the truck. (It's the hole that needs to be plugged for driving in deep water.) The drip was motor oil. It was dripping about 1 drop per second at first but quickly slowed and stopped after the truck cooled. I had been pushing the truck down the freeway at between 50 and 55 miles an hour for the past 2 hours. Given it only has 8000 miles on it since the truck was rebuilt in 1991 there are probably some dried out seals. I checked the dipstick and it showed a little over full after the truck cooled down so I felt comfortable driving it back. Should I replace the rear main seal just to be safe, or live with some oil dripping after long drives?

At first I wasn't too concerned. I figured maybe it needs a rear main seal and would get around to fixing it later. Now I'm concerned that the clutch may be contaminated with motor oil, or that gear oil and motor oil are mixing somewhere in the truck.

I assume that hole is a vent. Can oil drip from there normally or is this vent transmission related? Perhaps it being slightly overfull has caused the oil to leak out here. Any help is greatly appreciated.

 

[Divemaster920]

Not an air vent...air vents are on top. It is a dust vent.
No oil should not drip from there.
Curtis

 

[Jinx]

I wish there was a reputable deuce mechanic here in western Washington. Seems nobody knows how to work on these trucks. Grr.

 

[NDT]

YOU are going to have to become a "reputable deuce mechanic" . . . Before you do anything, make sure the oil level in the transmission is "one knuckle down" from the fill hole. If it is topped off, it will run out the input shaft.

If that does not solve it, yup, you are looking at a rear main seal replacement. I would drive it some more first to hope it goes away . . .

 

[Speddmon]

You should really read a post by gimpyrobb about pulling his transmission to clean his clutch from an overfull tranny. While he had it out he also changed the rear main. It's doesn't seem like it's that bad of a job, I'm doing mine today.

What I was getting to though is, the level of the tranny, "one knuckle down" would be fine for around town driving, but you should go closer to "two knuckles" for any extended high speed driving. gimpy had filled his to the "one knuckle" mark and after some extended hard driving it started leaking again because the gear oil expands so much when it get's hot.

Also, if you are not very mechanically inclined or just don't have the tools and equipment, If you know exactly the problem you are wanting fixed you can print off the appropriate pages from the TM and take them and the truck to a trusted mechanic. The TM's spell out the repairs step by step.

 

[jasonjc]

The eng oil needs too be check within 1 min of shut down. If you wait longer than that all the oil from the filter drain back and the level will be much higher than full.

 

[Jinx]

Okay guys, thanks for the help. I would love to fix it myself, but time and experience are lacking with me. I'm going to see if I can lure a deuce mechanic from Ft Lewis to work on my truck.

 

[Jinx]

After thinking it over, it was most likely gear oil and not motor oil as I first thought. It was a dark fluid, so it really could have been either motor oil or dirty gear fluid from the tranny. I was expecting the gear fluid to be a lighter color, but in hind site, when I checked the diffs, they were also a darker color. Also the fluid wasn't hot. If it was leaking from the motor, it should have been pretty hot, IMO.

If it was a leak from an over full tranny, or spillage due to a plugged vent, should I still have my tranny disassembled to clean any fluid that could have gotten on the clutch?

 

[Speddmon]

If it was tranny fluid (80w-90) you should be able to tell right away by the smell. If it was tranny fluid, you don't necessarily have to disassemble the tranny, just pull it and clean the clutch and flywheel really good with some brake parts cleaner. Also, make sure the vent on the top of the tranny is moving free.

 

[NDT]

I would not pull anything if the clutch is not slipping!

 

[Jinx]

The clutch is not slipping.

 

[Speddmon]

I would not pull anything if the clutch is not slipping!

I'll be making a new thread very soon, about pulling my transmission because of an overfull tranny and after I cleaned up the clutch and bellhousing with brake cleaner, my clutch wasn't slipping anymore either. But you really should read my post and see why it's important to check out unknown trucks....even going to the point of pulling the tranny if need be.

 

[NDT]

I'll be making a new thread very soon, about pulling my transmission because of an overfull tranny and after I cleaned up the clutch and bellhousing with brake cleaner, my clutch wasn't slipping anymore either. But you really should read my post and see why it's important to check out unknown trucks....even going to the point of pulling the tranny if need be.

I hear you, but . . . It's no fun pulling the transmission. Don't you think the clutch can recover from a one time oil soaking by just dripping dry and some driver induced slipping? Lots of the rebuilt deuces have the button disk with the non-asbestos linings, which don't absorb oil very well.

I'm not trying to contest your findings, just trying to find a shortcut . . .

 

[Speddmon]

I agree with you 100% that it should take a soaking and be just fine. I was talking about the unexpected problems you run into with a truck that you do not know the maintenance history of...read this thread I posted...Pulled the transmission today

 

[roscoe]

One of mine did the same thing on the trip back from WI. Clutch was slipping pretty good but pretty much stopped slipping the last 100 miles or so. Havn't noticed noticed the oil or clutch slipping since I got it home.