Transfer case replacement – Jeep Cherokee

Replacing a Jeep Cherokee Transfer case

Yesterday a friend called saying her transfer case was leaking. I was expecting a seal leak but it turned out that there was a hole in the case itself.

I had also planned to drive it to the shop but with the fluid rapidly exiting the case, I decided to trailer it. When I got there with the trailer, the ramps were frozen to the trailer bed. It took some banging to get them loose.

With her Jeep in the shop, I picked it up and inspected further. There was indeed a hole in the transfer case. It looked like it was punched from the inside. Although, it made no strange noises when I drove it on the trailer.

I began by draining the rest of the fluid. Then I supported the transmission. Next I removed the front and rear drive shafts. An 8MM hex wrench was all that was needed.

I then unbolted the transmission mount using a 13MM socket. Then I dropped the cross member by removing the 15MM bolts and nuts that hold it up. That gave me access to the transmission mount that is held to the transmission by two 18MM bolts. These bolts have thread locking compound on them and are hard to turn all the way out. I inspected the mount which is often broken in high mileage vehicles like this one but it was fine. Next I slipped the exhaust mount off the tab.

Rather than mess with the shift linkage bushing in the cold, I unbolted the shift lever from the transfer case. I selected 2wd and used a 9/16 wrench to remove the nut and washer. I carefully lowered the linkage out of the way.

Next I removed the speedometer drive by unbolting the 13MM retaining bolt and removing the clip. I left the sender attached to the wiring harness. I pulled the harness away from the mounting tab on top of the case. I unplugged the mode light switch and moved the wiring out of the way.

Next I unbolted the six 9/16 nuts that hold the case to the transmission. Five are accessed using a box end wrench. The last one is behind the transfers case shift linkage bracket and has to be accessed using a 9/16 socket and a long extension. The two near the exhaust pipe take some patience to get off unless you remove the exhaust pipe. Since this one was in good shape and welded in place, I left it alone. Lowering the case down helps get access to these two nuts.

With the six nuts off, the transfer case slides easily off the transmission. I then prepared the replacement case to go back in by putting it in 4wd. This allowed me to rotate the front yoke and make the input splines turn to line them up. With the replacement case in place I started a nut to hold in there.

Next I tightened all six nuts. I then reinstalled the shift linkage, wiring harness and speedometer drive. I then reinstalled the front drive shaft as it is easier to access with the cross member out of the way. I filled the transfer case with fluid before putting up the rear drive shaft as it is easier to get the bottle in place with out the drive shaft in the way. The 231 holds a little more than a quart of ATF.

I then put up the exhaust bracket and transmission mount. Again, these bolts are hard to turn due to the thread locking compound on them. I then put up the cross member and bolted it to the body before lowering the weight of the transmission onto the cross member. I then reinstalled the four nuts that hold the transmission mount to the cross member.

Then, I reinstalled the rear drive shaft. I checked for leaks and loose bolts and then lowered the Jeep for a test drive. The replacement transfer case worked fine and shifted to all gears with out adjusting the linkage.

I plan to pull the broken transfer case apart to see what caused the hole. I will post an update when I do that.
[phpbay]jeep transfer case, 10[/phpbay]