The oil seal on the rear output shaft of my transfer case is leaking. It's leaking out just forward of the front universal joint on the rear driveshaft. Then of course the oil gets whipped around all under the truck. Is this a DIY job? Any special tools required? I don't have to pull the t case do I? Any tutorials on here?

 

I pulled the flange off, popped out the old seal, carefully tapped the new one in, greazed the inner surface, used silicone on the shaft, reinstalled flange, torqued to spec. Good togo. Make sure to inspect the flange/seal mating surface for burrs and galls.

Before you do anything make sure the oil level is not too high, as excess will start pushing out at that seal. I followed the Marlins salesmans advice when I put the duals in and over filled it.

 

Thanks. Sounds pretty self explanatory.

Does the shaft come out easily once you un-bolt the U joint from the drive shaft? I'm a bit worried that I wouldn't line up the splines right with the drive shaft? Or is it that if the bolts on the u joint match up, the splines are automatically aligned? Also, what keeps one from tapping the seal in too far? Just go easy and stop when it's flush?

Where did you get the seal?

 

The flange splines and drive shaft splines are apples and oranges, two different things. There is a 26mm (If I remember correctly, had to buy the socket), not much special about the splines and flange nothing to line up. I siliconed the shaft. I was driving cross country and thought the leak was worse than it probably was but was a freshly rebuilt t-case from Marlin. So replaced it in the parking lot of Minard's in Souix Falls found the seal at a local parts store. Locked my keys in the truck at the same time. That took longer to undo than the seal replacement.

 

Ha, Ok doesn't sound hard. So I am to coat the splines of the output shaft with silicone? Like Permatex RTV? This seems odd to me as my experiece with RTV is that it is to serve as a gasket between two fixed metal surfaces. Wont the RTV mix in with the gear oil? Please pardon my ignorance as I am having a hard time envisioning this in my mind.

 

Alright, just went out to the driveway and removed the flange nuts and dropped the driveshaft. Now I can see what I'm dealing with. Looks easy. But how in the heck am I going to get that staked nut off? How do I unstake it and what size is the nut?

 

I used a small screw driver to unstake. Beleive the socket size is 26mm. I had to buy one.

 

a 1&3/16 socket will work too, also before you put the flange back on put some rtv on the shaft where it necks down to the spline, then put the companion flange on and torque to 90 ft lbs. That little bit of rtv will help leakage as well. Marlin Crawlers heavy duty seal is the best. The FSM calls for seal packing but rtv will do..

 

Another question, I had a 1 1/4" socket and gave that a good but gentle crank on the nut. With some grunting, it just turned the flange around. So how do I break that nut loose without turning the flange? Put it in 4x4?

So stick a small flat screwdriver in the staked part (will probably have to beat on it with a hammer) and pry it out? Is there any danger in boogering up the threads of the shaft?

 

put 2 flange bolts back in and using something to get leverage on them as you loose the nut

 

Lock in 4x4 4wd with hubs locked, put on parking brake to, and chalk the tires. If you only put the screw driver where the nut is staked no you won't booger the thread. The threads on the nut are already boogered. I used loctite instead of restaking, I don't like hammering on bearing surfaces.

 

You guys sure are helpful. Thanks!

Would it do any harm to use an impact gun to take that staked nut off?

 

Don't see why an impact would hurt it, if I'd had one I'd've used to for sho.

 

Thanks. Man I'm really having a hard time unstaking that darn nut. It is really smashed against the shaft. I can't get a srewdriver in between it and the shaft to pry the dent out. With an impact gun I could probably just run it right off and the staked indentation of the softer brass nut would probably back out in the process. But the last thing I want to do is ruin that output shaft.

I'm with you and I'm using loctite on the new one. That stake method is lame!

 

after you have driven it awhile recheck the nut, check to see if you have any play in the flange

 

I just did the front output seal, I used the air hammer with a pointed punch to unstake the nut, messed it up a bit but I re-used it anyhow, I would probably buy a new one if you use that method. I used the impact to remove the nut after un-staking best I could.

Mine took a 30mm thin walled impact socket, but I've got a 3.0.

 

Transfer case input/output flange nuts = 30mm(same as an 8" 3rd member companion flange/pinion nut)

1 1/4"(1.25") is close enough to 30mm(1.18") and also will work.

Front axle IFS 7.5" companion flange/pinion nut = 24mm(.94") but 15/16"(.93") is close enough to work too.

13/16" is too small for any of them. 26mm is not big enough for the nuts on the transfer case input/output or the 8" companion flange/pinion nut, and too big for the one on the 7.5".

 

just finished this job, pretty easy, except for the local Toyota dealer giving me the wrong parts. Fortunately the local Napa had the seal in stock.

So tell me, what is to keep the oil from leaking out of the mating surface between the outer rim of the seal and the transfer case housing? It is just metal on metal. No gasket, no rubber. I can see how the inner rubber ring of the seal will seal against the flange surface, but it seems to me it could leak outside the seal. I know it presses into place, but I've just never seen a metal on metal mating surface that would hold oil.

 

The gasket I got from Marlin Crawler is encased in rubber with a metal core. The stock one I took out was similar, are you sure its metal to metal

 

Yep, metal to metal. Just like the old one I took out.