Front hubs not disengaging?

[kingsxwc]

Recently purchased 96 cherokee 4L 5spd 4X4 with "command-trac" part-time 4WD and NP-231 transfer-case. Vehicle has 93K mi. I'm not sure if the front hubs are disengaging. The front drive-shaft turns when the front wheels turn even in 2wd. Also, the part-time 4wd light comes on instantly when the lever is pulled. I would think since it has a vac actuator it should take a second or two before the light comes on. When in 4wd, it does seem to work normally. Where does the 4wd indicator light get it's signal from?

[hiduke89]

i have n 89 and mine comes on instanly too. even when my 4wd wasn't working it still came on so i think it is just automatic when the lever is pulled

[Edbrooks]

Originally Posted by kingsxwc

Recently purchased 96 cherokee 4L 5spd 4X4 with "command-trac" part-time 4WD and NP-231 transfer-case. Vehicle has 93K mi. I'm not sure if the front hubs are disengaging. The front drive-shaft turns when the front wheels turn even in 2wd. Also, the part-time 4wd light comes on instantly when the lever is pulled. I would think since it has a vac actuator it should take a second or two before the light comes on. When in 4wd, it does seem to work normally. Where does the 4wd indicator light get it's signal from?

If it feels as though it is binding in a moderate, slow-speed turn, you are right, the hubs are not disengaging. The transfer case is mechanical. The 4wd light is turned on by vacuum. On earlier models this switch is located on the passenger side, under the hood, beneath the blower motor.

The likely problem (my guess) is the shifter motor on the front axle, right side, is not disengaging. It is vacuum operated. The vacuum lines tend to crud up over the years. You can remove them and check them to be sure they are clear. Another possibility is there is no grease in the shifter motor compartment. It uses 90 wt axle grease. Remove the shifter motor - that's easy - and while you have it off you can check it for proper operation. And put new grease in there. Slide the locking collar back and forth a few times to work the grease in.

While the shifter motor is off, start the engine. Shift the TC into 4wd. The shifter fork in the shifter motor should move. (Easiest if you have someone else in the vehicle - you do not have to move the vehicle and the trans can remain in park) Then have that person shift it back to 2wd. The shifter fork should move in the opposite direction. If it doesn't, you either have plugged vacuum lines or a defective shifter motor. You can check the shifter motor by disconnecting it entirely and putting vacuum (your lips will do!) on the vacuum lines and try to work the motor. It doesn't take much suction to move it. All this is a quick and easy check.

Vacuum TO the shifter motor, as well as to the 4wd light switch, comes through a vacuum harness that is connected at the rear left side of the transfer case. Moving the TC lever operates a vacuum switch that turns this vacuum on or off. I had to replace the switch on my Cherokee (60 bucks) AND the big vacuum harness, as the plug was cracked. (Another 50 bucks.)

[kingsxwc]

Thanks for the advice! I'll take a look at it this weekend.