Why your transmission leaks oil

[Westech]

Well as most of you know I had transmission issues on the way to and from Ohio last week. My transmission was leaking oil out the input shaft and on to the clutch.
Today we removed the transmission and found out why the transmission was leaking. it was not due to being over full. It was due to the last person to work on the transmission installing parts wrong.

The deuce transmission DOES has a input shaft seal. It is called a Mechanical seal. There is no rubber seal, it uses the oil to seal it self. How it works is the input shaft cover is tapped so that the oil comes down the shaft.. is spun on the housing and the tapped threads force the oil back in to the transmission. It is like you blowing in to a fan... the fan is blowing back and forcing your hot nasty breath back in your face. There is a drain hole in the housing so if yours is leaking make sure the drain is not plugged also.

The input shaft cover also holds the front bearing in place.

What was wrong with my transmission is that some NOOB used Gasket maker on the input shaft cover. When that is used the input shaft cover is not aligned to the input shaft and the seal will not work. The tolerances are VERY tight. My cover was also just nicking the input shaft. we were able to machine everything back so that they should work. "should"

When installing any of the transmission covers or housings NEVER use RTV. This is a paper only type of fit.
I was able to cut new gaskets out of paper to finish this job.

 

[doghead]

Friggin newbs

 

[gimpyrobb]

I have an input shaft I can send if needed.

 

[ODdave]

What am i missing? No seal in there? How the **** is this worth a **** in a fording situation?

 

[Westech]

The bell housing is sealed when fording. Hence the plug at the bottom and every part being sealed with a paper gasket.


Thanks Gimp.. we machined everything so we think it will work. I am only .002 out of spec. My friend Jeff deals with Mechanical seals every day and he said they need to be aligned 100% perfect more then anything. A size difference on one side is what causes them to leak.

 

[DieselBob]

In theory water shouldn't enter the bell housing area. The stater, bell housing, inspection plate and SAE adapter ring all have gaskets to prevent water entering.

 

[ODdave]

......brain fart.......

 

[gimpyrobb]

Your a stinky beotch!

 

[General Mcgregor]

Mine leaks at the boots on the PTO.

 

[DieselBob]

Mine leaks at the boots on the PTO.

That should be a seal problem. The TM 9-2520-246-34-1, page 2-321 shows a seal plus the boot on each end of the shift shaft.

 

[General Mcgregor]

Awesome, Thanks for the reference!!!

 

[DieselBob]

Glad to help. That's what it's all about.

 

[gringeltaube]

............................................This is a paper only type of fit...................................

Let me say this:

YES, half a century ago when these transmissions were factory assembled or rebuilt, using all NEW parts, they sure used the correct thickness paper gaskets and it works well (for some time)....

YES, you can replace that gasket with any modern gasket maker but then the retainer has to be modified first. Otherwise it WILL bottom out against the bearing BEFORE it touches the housing's face and possibly end up seriously deformed.

FYI 90% of all used retainers, especially the very early ones, have their flange warped and should be re-surfaced anyways before reinstall. Also, putting in a new paper gasket alone without measuring the required thickness is asking for trouble. To thin it may still leak; to thick and the bearing will stay loose in the housing...!

The deuce transmission DOES has a input shaft seal. It is called a Mechanical seal. There is no rubber seal, it uses the oil to seal it self......................
......... they need to be aligned 100% perfect more then anything. A size difference on one side is what causes them to leak.

I beg to differ..... there is no mechanical seal and concentricity is not that critical here, IMHO...


G.

 

[greg2560]

The way I see it the tranny was over full run 1 to 2 in below the fill plug no leaks. Where is the air going to come from to blow the oil back in? Behind the bearing is a rifling there right that allows the oil to run back in the case that hit the front wall. Gears will spin the oil up not to the front and rear right. The notch in the front is to allow the oil that gets to the other side of the front bearing to run back in the case through the bearing. Humm Yup Over full just my 2 cents.. little fyi http://www.mechanicalseals.net/

 

[Westech]

Well that is what my Friend called it. he machines them every day in t PTO and input shaft housings. It may not be the type of seal you pictured in your link but it is a seal. It uses the rotating force of the input shaft to move the oil back in to the transmission.
I have had a few other deuces that I filled right to the top and never had a problem.

 

[gringeltaube]

.........I have had a few other deuces that I filled right to the top and never had a problem.

Same here..... filled till it starts overflowing out of the inspection hole!

Whatever we call that "seal".... it sure works: once, in a completely different application I wanted to run a tranny backwards, that is spinning the input shaft CCW at 1400rpm.... almost instantly I had a small stream coming out, and most certain it would have "pumped" itself way low in a short while. Rotation inverted to CW, same speed, oil would immediately stop leaking. That same tranny, little overfilled and real warm, still had 0 leaks!

Topic related: http://www.steelsoldiers.com/deuce/52980-leak-bellhousing-2.html#post647637

G.

 

[73m819]

Another thought on these tranny leaks is the VENT, that gets plugged or even sticky where it opens late after pressure has started to build WILL cause leaks where ever the pressure can find a place to escape, like a SLIGHTLY worn seal that would hold fine under normal pressure

I think these VENTS cause more leaks and trouble then thay are worth, I'm for removing ALL the vents (axles,ect) and running a vent LINE that ties ALL the VENT locations in up to the fire wall, once done, the LEAKING of SEALS will go way down, If a seal is leaking now, you can be pretty sure that the seal is worn out.

 

[GoinNutts]

If it don't leak how ya gonna know der is oil in der! When she stops leakin that is when I worry!

 

[greg2560]

If it don't leak how ya gonna know der is oil in der! When she stops leakin that is when I worry!

 

[runk]

This was a common "seal" on British cars of the era. A good article about the modification commonly done for the rear main seal on the Triumph 4 cylinders-
Rear Seals