Can a single piece transfer case ever be leak free?

[cruiser_guy]

I've been fighting to make the transfer case on the FJ55 leak free for the past year ever since I did the H41 swap (necessitated because I screwed up when I reassembled the original H42 4 years ago and left out a spacer). One thing that needs to be mentioned here is that the transfer case is a 4 speed case with three speed gears which may be contributing to my problems (it was tough getting the right clearances on all the gears and the transfer case was stuck to it's original tranny so good with silicone that I bent my transfer case puller removing it!!).

Today I picked up a set of seals and the gasket kit for the transfer case from the local Toyota dealer and I'm going to rebuild a 3 speed case I picked up in Oregon this summer and swap that for the 4 speed case/3 speed gears I have now.

What particular things do I need to watch for? I've had the output bearing retainer machined for dual seals and the parking brake drum has been sleeved. I'll be following the FSM and replacing all "O" rings as I go along. When shimming the output bearing is it better too tight or too loose (I'd lean towards too tight if I could not get it right on)?

I just want a transfer case that doesn't leak oil all the time. I know it's possible because my BJ60 is usually leak free. IH8 oil leaks!!

Any other areas that are leak prone in the single piece cases?

 

[PhrogsPhorever]

Cruisers leak, it's what they do

3 diesel cruisers? You suck

edit: Good work that you do in Guatemala

 

[cruiser_guy]

Come on folks!! Someone else out there must have at least tried to stop the oil leaks?

 

[Coolerman]

It's like any other gasket sealed unit:

Sealing surfaces need to be smooth, clean, and flat.
Gaskets need to fit.
Covers need to be torqued in the proper sequence, and to the proper torque.
I have found that putting a THIN coat of silicone on both sides of the gaskets help.

Rubber seals need to be installed square in their bores and the surface they ride on must be smooth and in spec.

Some say to seal the input/output shaft splines with some silicone to prevent oil from creeping past them.

It's still going to leak eventually.... It could be worse, it could leak like a Corvair or a Land Rover...

 

[spotcruiser]

It's very doable. Just do a good installation of the seal kit. Be especially careful with the o-rings for the idler shaft and shift rail (lube them well for installation). Get the input seal in the correct way (face of seal to xfer). Do the double output seal (as you mentioned). Put RTV under the output shaft nut. Use care not to damage the input seal when mating the xfer and tranny.

Set output preload to FSM spec.

 

[dgangle]

After rebuilding, new seals, etc I could not get the end of the idler shaft to stop leaking. Finally I cleaned it with some brake cleaner and gooped it up with silicone sealer/forma-gasket. Not pretty but problem solved.

 

[bustanutley]

it is important to get the correct preload on both output shafts.

 

[cruiser_guy]

It could be worse, it could leak like a Corvair or a Land Rover...

It seems like it's that bad!!

 

[Trollhole]

After rebuilding, new seals, etc I could not get the end of the idler shaft to stop leaking. Finally I cleaned it with some brake cleaner and gooped it up with silicone sealer/forma-gasket. Not pretty but problem solved.

I found that some of the o-rings that come in some of the off brand rebuild kits have defects or poor idler o-ring. Also installation can cause issues. If the o-ring gets caught on the lip of the t-case it can tear the o=ring. Also any pressure buildup in the case will cause it to come out. If mud gets packed up on top of the cover and closes the vent off it will cause leaking especially if you have installed a T-case saver. If you have installed a vent tube make sure it has no restriction.

If your parking brake drum or front input flange have any rust on them they will eat that new seal you installed.


I always apply a coating of grease to the inside of the seals. Helps them from wearing during initial run.

RTV on the output splines.

As has been stated a thin coat of RTV on the gaskets will help in preventing leaking. Proper torque specs helps a lot.

Stick with preload specs.


Do it right once and don't worry about it for another 75K

 

[mano002]

Is the vent on your t-case working properly? if not, then changes in temperature will create pressure in teh t-case and force oil out, making it leak even faster.

 

[crushr]

I rebuilt my 3 speed xfer case about 10 years ago, and it doesn't leak other than a bit of seepage around the drum. I wish the rest of the truck was as leak free.

 

[cruiser_guy]

I'm in process of tearing down my spare three speed transfer case. I've done this enough but with this case I'm having a little trouble removing the output shaft. In all other cases a couple of sharp raps with the hammer and it popped out, this time I've wailed on it and it has not budged!

I was going to try pressing it out but I don't want to break anything. I do not have the SST shown in the manual (09318-60011) to support the gear when pressing out the shaft. Anyone have dimensions of this tool so I can make one?

 

[Coolerman]

Page 2 of 2 Rebuilding a 3sp T-case

I did not use a SST, just placed enough 'shims' to support the gear.

 

[nuclearlemon]

after a rebuild, expect about three months of leak free before it starts again

 

[cruiser_guy]

after a rebuild, expect about three months of leak free before it starts again

Nnnnooooooooo!!!!!!!!!

 

[IDave]

Coolerman's doesn't leak because his has been sitting on the garage floor for 6 years.

Mine always start leaking again after a while. It's not if, it's how much.

 

[pbgbottle]

mine was leaking out of the frost plug thingy on the front side of the case. replaced and the leaks where gone.

 

[vk7ybi]

Throw one of these in the front output too.. https://forum.ih8mud.com/40-55-series-tech/245505-marlin-hd-pinion-seals.html

 

[cruiser_guy]

Well it appears to have stopped leaking since I pulled the vent thingy with the spring and rubber disk off the top. Of course it didn't stop until my spare case was all rebuilt first. I guess I'll put on an extended breather and not worry about the vent any longer.

I'll save the extra rebuilt 3 speed case for another day.