After eliminating leaks in my NP231 from the rear and front output shafts, I still had one at the range selector (shifter) shaft. Here's how to replace it with the transfer case still on the Jeep. (Apologies in advance for the poor focus of some of the shots. It's hard to hold the tools with one hand, hold the camera with the other hand, and click the shutter with a third hand.)
The seal consists of an O-ring and a plastic retainer ring. You'll need one of each (I bought two of each, because that's what I do with O-rings and seals.)
You'll need to remove the skid plate. Support the transmission with a jack or jack stand, remove the four nuts that hold the transmission mount to the skid, take out the six bolts that hold the skid plate to the frame. I use a floor jack to support the transmission and a motorcycle lift to support, raise, and lower the skid plate.
Here's the space you have to work with. It's tight, but the good news is you can do this without removing the drive shaft or front output yoke. (It would be much easier that way though.)
This nut has to come off.
Working over the driveshaft I was able to get a 14mm socket on it using an extension with a wobble joint.
When you have the nut off, slip the selector lever off the shaft. It has a slot to index it, so no need for the red indexing marks I applied. The shaft was pretty juicy, confirming the leak.
Getting the retainer ring out is probably the hardest part of the whole operation. There's not much surface area to the ring and you don't want to nick or score the shaft or case. Small picks just bend, heating one and jamming it in didn't work, so finally I used an awl and carefully tapped it in, and then was able to pry out the ring.
Next fish out the O-ring (t's the black blob at the bottom of the shaft.)
I applied assembly lube to the O-ring and pushed it in place using a wooden coffee stirrer.
More assembly lube on the retainer ring, then started it by hand. I seated it all the way using a 3/4 socket on an extension. It pushed right in without having to tap on it.
You're done. Reassemble in reverse order.
The seal consists of an O-ring and a plastic retainer ring. You'll need one of each (I bought two of each, because that's what I do with O-rings and seals.)
You'll need to remove the skid plate. Support the transmission with a jack or jack stand, remove the four nuts that hold the transmission mount to the skid, take out the six bolts that hold the skid plate to the frame. I use a floor jack to support the transmission and a motorcycle lift to support, raise, and lower the skid plate.
Here's the space you have to work with. It's tight, but the good news is you can do this without removing the drive shaft or front output yoke. (It would be much easier that way though.)
This nut has to come off.
Working over the driveshaft I was able to get a 14mm socket on it using an extension with a wobble joint.
When you have the nut off, slip the selector lever off the shaft. It has a slot to index it, so no need for the red indexing marks I applied. The shaft was pretty juicy, confirming the leak.
Getting the retainer ring out is probably the hardest part of the whole operation. There's not much surface area to the ring and you don't want to nick or score the shaft or case. Small picks just bend, heating one and jamming it in didn't work, so finally I used an awl and carefully tapped it in, and then was able to pry out the ring.
Next fish out the O-ring (t's the black blob at the bottom of the shaft.)
I applied assembly lube to the O-ring and pushed it in place using a wooden coffee stirrer.
More assembly lube on the retainer ring, then started it by hand. I seated it all the way using a 3/4 socket on an extension. It pushed right in without having to tap on it.
You're done. Reassemble in reverse order.
