T18A Input shaft leaks. Cant get it to stop.

[dsrt4]

I have a t18a in a jeep of a buddy's I am working on.

I have been around and worked on this jeep for years with him. We essentially are at wits end with a input shaft leak. When we got it years ago it had a Novak 350 conversion kit on it. We pulled all of it off and stuck a rebuild kit into it and bought a stock jeep t18a shaft ,bearing retainer and T-150 bell housing for it.

A new stock bearing retainer and seal was put in from Novak. It has always leaked. Not a lot but just enough to drive him mad. We'd pull it and replace the seal and clean the clutch or buy a new bearing retainer and seal and clean the clutch.


Now that I got my jeep out of mothballs and he did as well and the leak issue that was forgotten has now reared its head.


This things has the exact same parts as any other t18a including mine but it leaks at the input shaft. Mines been dry since I rebuilt it. It's like the seal rides too far back on the input shaft and it deforms the seal. It does have a gasket on the retainer.

Other than the leak the Transmission shifts and runs great.

Is the a sealed input shaft bearing we can put in the front of this stupid thing? It's obvious the new seals and caps aren't working. Novak has never been any help with the issue. It's leaking out front end of the bearing retainer tube getting past the seal in the bearing retainer.

Didn't the T-98 guys find a sealed bearing that would work? Any chance it's the same input shaft bearing ? We are both getting too old to be yanking this beast out all the time especially since we are older. Me 40 and not in great health and him 60.

 

[Hedgehog]

It seems to me that there must be something wrong with either the diameter of the input shaft, at the seal location, or there is a problem with the bearing retainer. I'd be looking for a stock bearing retainer. The Ford version could be cut/turned to T18a spec's.

 

[dsrt4]

The Novak bearing retainer was supposed to be just a stock replacement. The shaft was a nos piece. The seal had a decent interference fit on it when we first installed it.

The second replacement retainer was a used stock CJ7 piece
Bought on eBay in its infancy. It all was really pretty much the same.

We thought the Transmission was pressurizing some how but that didn't help either. Pilot bushings swapped you name it we tried it.

A sealed input shaft bearing would put a end to it all I would think.

 

[Lumpy Grits]

How much end-play(front to back)do you have on this shaft.
Also-Have you ck'd the pilot bearing for wear?
LG

 

[dsrt4]

The Transmission was completely rebuilt when we did the install. I don't remember any excessive play in it back and forth.

Pilot bushing was replaced everytime we yanked it. I would assume it has maybe 300 miles on it since the last time we did it and it got put up?

It's super smooth in top gear. No rattling or anything like excessive side to side play in the shaft.

 

[Lumpy Grits]

Have you ck'd the oil level of this tranny to be sure it's not overfilled?
Are you sure the tranny's vent line is not clogged?
LG

 

[dsrt4]

It's as full as mine is. Just a little below threads.

It has a extended vent line on the Transmission . We put that on thinking the Transmission might be pressurizing just enough to get it to come out. I know it was clear last time I looked at it and blew through it.

 

[Hedgehog]

Lets be completely honest here. If the Transmission were as perfect as you believe it is, it wouldn't leak. Simple as that. But it does leak and I bet it's something simple, but being a Transmission a pain to figure out.

Since you've already replaced the bearing retainer with a stock item that eliminated that as a possible problem. I assume you are using the correct pilot bushing/bearing for the T18a. So something is moving or as Lumpy asked the pressure release or breather is not functioning correctly building pressure up in the Transmission or there is to much fluid in there.

If the fluid level is good and the thing is breathing (the breather is on the shifter lid to the rear on the drivers side) something isn't right with the rebuild. Again, it will be something simple like end play. In working on my T18a Rob said that rebuilding kits frequently come one spacer short. Usually the one between the main shaft and the input shaft. Its sorta there to hold the needle bearings in place inside the cup at the rear of the input shaft. I.E. you might have to do another Transmission rebuild, but just the top or the main shaft. I bet nothing is warn out, but very possibly a forgotten spacer or snap ring.

Edit: You typed while I typed some of the above. It is apparent that you have already picked the proverbial low hanging fruit. Now it's time to dig deeper. As you probably already know, the T18a is worth the effort.

 

[Hedgehog]

Additional thoughts.

The Transmission and the Transfer Case have their own breathers. Make sure BOTH are clear.

What weight fluid are you using and make sure you are using dino oil and not synthetic. Synthetic oil can get out where regular dino oil can't.

Something simple ..... Is the seal in the correct way? the spring should be facing the Transmission .

 

[dsrt4]

It's a runner for sure. It's a whole lot smoother running than mine. Other than the leak it's fantastic.

I've been all over it. In the jeep and out. It's something we have messed with for 25 + years I bet.

It definitely has the correct input shaft pilot. It's the same one as mine.

His case breather is extended also but I'll check again.
Seal is in correctly. It's crazy. It's been the talk of many a campfire during wheeling trips of past.

 

[Lumpy Grits]

It's as full as mine is. Just a little below threads.

It has a extended vent line on the Transmission . We put that on thinking the Transmission might be pressurizing just enough to get it to come out. I know it was clear last time I looked at it and blew through it.

WHEN was the last time the oil level was ck'd???????
What about the t'case oil level?
Separate the vent lines and shorten the one for the tranny. Drive it for a spell and see what's, what.
BTW: What oil are you using?
How long after the install of this rebuild, did it start leak'n.
Was this a 'pro' rebuild or?
LG

 

[Lumpy Grits]

It's a runner for sure. It's a whole lot smoother running than mine. Other than the leak it's fantastic.

I've been all over it. In the jeep and out. It's something we have messed with for 25 + years I bet.

It definitely has the correct input shaft pilot. It's the same one as mine.

His case breather is extended also but I'll check again.
Seal is in correctly. It's crazy. It's been the talk of many a campfire during wheeling trips of past.

The seal could have a crack at the lip.
How much oil is leaking out? Puddles or a few drips?
IF drips-get some Lucas power steering stop leak. Drain the tranny enough to use the whole bottle and in about 200-300 miles the leak will stop.
LG

 

[Hedgehog]

I truly want it to be something like a breather, but in reality the T18a isn't sealed at all. The top/stick pivot has no seal. Many T-18 's were ruined, mine is almost an example, from water, usually rain, running down the stick and right into the Transmission . That's one reason to try and keep a new boot on your Transmission . So, if water can get in, air pressure can get out.

lets not be so sure about the seal being in correctly, I've seen'em in backwards.

 

[Lumpy Grits]

THX HH for the info.
I've only pulled a few T-18 's, and never rebuilt one.
LG

 

[dsrt4]

WHEN was the last time the oil level was ck'd???????
What about the t'case oil level?
Separate the vent lines and shorten the one for the tranny. Drive it for a spell and see what's, what.
BTW: What oil are you using?
How long after the install of this rebuild, did it start leak'n.
Was this a 'pro' rebuild or?
LG

75w 90. It was rebuilt by a local shop using a kit from Hicks 4X4 out of LA.

Nothing is missing in the Transmission . It's been been apart with mine on the bench as guide. Hicks thought it was end play in the Transmission but it's pretty tight.

It isn't missing a ton of oil. I could bend my pinky knuckle down and touch it. The seal is for sure in right. I have mine in the same way.

 

[Hedgehog]

This was a problem with the boards new posting issue. Please disregard.

 

[Hedgehog]

Rob at Willys Works pointed out how many "Never been driven in water" transmissions are ruined by simple rain water entering the Transmission through the stick.

 

[Hedgehog]

Then the Transmission is perfect and isn't leaking. Then where IS the oil coming from? Are you sure it isn't coming from the other direction like a leaking main seal?

 

[dsrt4]

Lol!

No. It's leaking and it's coming out of the bearing retainer snout . Some how its getting past the seal .

His rear main is dry as bone.

I guess I'll tear it apart one more time and then run the oil low and see if that does anything. Maybe we should have kept the sbc junk it had on it and swapped in a 4 bolt.

 

[Lumpy Grits]

75w 90. It was rebuilt by a local shop using a kit from Hicks 4X4 out of LA.

Nothing is missing in the Transmission . It's been been apart with mine on the bench as guide. Hicks thought it was end play in the Transmission but it's pretty tight.

It isn't missing a ton of oil. I could bend my pinky knuckle down and touch it. The seal is for sure in right. I have mine in the same way.

If everydangthing was 'rite'. Then it wouldn't be leak'n.
LG