tranny/tcase seal

The shop that I brought the 5 to to have the axle bearing replaced noticed that my tranny was a little loud so they checked the lube levels in the tranny and tcase and found that the tranny was low and the tcase was high= bad seal b/w the tranny and tcase. How easy is it to replace? Concievably it should involve nothing more than removing the tcase, replacing the seal and slappin it all back together. Is it that easy? BTW, a t15 tranny and a dana 20 tcase.

Karl

 

what year is your Jeep?
a T15 and D20 should only have the gasket between the two units
there are no seals
seals are only used when there is an adapter of some sort and/or different fluids involved between the two
oil will flow between the two units, this is normal
and yes, the transfer case will appear to be overfull
I seem to recall some differences in the gasket, this had to do with covering up of the oil transfer hole, can't recall which Jeep models though
I would pull the transfer case fill plug first, let it run, then reinstall
then I would fill the trans to the fill hole
now you know both are full with no chance in overfilling
my 0.2 worth

 

My '5 is a '74. The steps that you describe are how I filled the two to begin with. I was not sure that there was a fluid transfer hole between the two. I have a t18/d20 in the shed that I have separated and a dont recall a fluid transfer hole. In fact there was no gasket, just rtv. Hmm, I guess I will just have to keep a close eye on it. Thanks for your 2 cents.

Karl

 

The fluids are seperate on mine. I've got a factory T-18 & Dana 20. I know for sure because I got water in the transmission once that turned the oil milky & frothy, but the transfer case oil looked normal. In fact, I drain & refill them seperately, too.

Eric.

 

the T18 and D20 combo is different
there is a seal in the adapter to keep the transmission from being overfilled by transfer case oil

 

I don't know that there is a passage specifically between the two, but oil can transfer slowly through the bearings. It is possible for the transmission to be dry and the transfer case be ok due to the TC being lower. The transmission will fail first (don't ask).

 

This is the second time this has happened. After reviewing my tsm there is no seal between the two, fluid should be able to communicate between the two via the bearing. As for puking between the two there is no mention. The only thing I managed to dream up is that the vent on the tranny might be painted shut (the tranny was painted during a partial resto) and because the gases that a tranny generates from heat and sloshing gears through gear oil and so on are pushing the oil into the tcase. Any other reasons that it could be would be appreciated.

Karl

 

Nope. There is a seal between the two just like the stock T-18's. It seals around the spacer that goes between the rear output bearing of the tranny and the input bearing of a small hole 18 or the T-86 bearing and retainer on the rear of the adapter for the large hole case. Oil can seep past the bearing as mentioned and work it's way into the transfer case though. Never heard of it going the other way as the oil level in the transfer case is normally low enough to keep it from happening.
Regarding the T-15 to 20 oil transfer, you can put in a sealed rear output bearing on the tranny. It probably won't stop it completely, but should slow it WAY down. I have to do this on my Saginaw 4 speed and Dana 18 or I have the same problem. Nickmil.

 

Ok, I have looked really hard for a vent on my T15 and I could not find it. Could someone give ne a hint? If there isn't one I can pull the TSC switch (like the reverse switch but on the 3rd gear shift rod and it was originally supposed to change the timing when in high gear) and use that, but is that a good idea? I dont have an extra vent what could I use? I could put a tubing fitting in and add a length of fuel line like a diff. Any thoughts?

Karl

 

There was only a gasket between mt t-15 and Dana 20 and I think that the oil was seperate I do remember though that you will have to drain both the Trans and the T-case if you are removing the t-case the lower drivers side bolt from the tcase to the trans will drain the trans when un bolted. also remember there are 5 bolts holding the Tcase up the fifth one is pretty tricky to spot and you will have to remove the Tcse shifter assembly to get to it.

J.T.