Questions and Answers

Jeep Cherokee Noisy Transfer Case Q. First off I want to thank you for your service. I had read a response to a question about a Cherokee that did not want to start all the time. Two years of this passed by and after replacing the CPS, on your advice, the problem was fixed. Thanks!

My issue is with my 1990 Jeep Cherokee 4x4 with 198,000 miles. I am not ready to retire it. My 4x4 slips. You put it in 4WD, and if you drive slowly it will drive fine. If you give it any juice the Jeep shakes and you hear this tremendous clunking sound like a chain rolling over a rounded gear or two gears that aren't meshing nicely. I really can't tell where it is coming from. I realize I have two options here.

The only related history I can give is I used to drive a lot in the mountains of Colorado. I would drive down highway 285 which would have patches of ice so I would leave the 4x4 on all the time. I know it is a part time system. What do you think the problem might be? I like to fix my own vehicles, so I haven't taken it to a shop.

Regards,
Brian

A. Your analogy "a chain rolling over a rounded gear" is an apt one. Because that is exactly what is happening. 4WD vehicles are not designed to be run on dry roads for any length of time. This puts an enormous amount of stress on the internal parts of the transfer case.

Because of this stress, the main shaft sprocket, front output shaft sprocket and drive chain have worn almost completely out.

The mainshaft sprocket, front output shaft sprocket and drive chain can be replaced, but in this case I think your best bet would be to get a low milage used transfer case from a junk yard.

There were two different transfer cases used in that truck. A New Process (NP-231) Synchronized and a New Process (NP-242).

Make sure you get the right one. A circular ID tag is attached to the rear case of each transfer case. The ID tag provides the transfer case model number, assembly number, serial number, and low range ratio. The transfer case serial number also represents the date of build.