transfer case motor

[hinkleboys]

How do I know if the transfer case motor is bad? I have no switch problems, no "service 4wd light" on dash, (so I don't think its the TCCM); checked the actuator and it's kicking in when removed from the front axle. I have no idea what the sounds should be when I switch from 2 wheel drive to A4WD, to 4HI, to 4LO but when I switch from 2 to A4WD you can hear the actuator kick in the there's some noise coming from the transfer case that sounds like the motor is burnt up, but honestly, I don't know. Any suggestions?

 

[C-ya]

You should be hearing two sets of sounds, one from the transfer case and one from the front disconnect. If you are hearing the front disco, and nothing from the xfer case, try pulling the motor off of the TC and see if it moves when commanded. That will tell you if the motor is bad or if something in the TC is bound/broken and not allowing the motor to turn. Proceed from there are results indicate. If you are not getting any lights, it seems like things are moving just enough to satisfy the limit switches that look for movement, but that seems odd since nothing seems to really be moving.

You should only hear the sounds when going to or from 2WD. Once in 4WD, the changes are internal and you will not hear anything.

 

[IllogicTC]

You should be hearing two sets of sounds, one from the transfer case and one from the front disconnect. If you are hearing the front disco, and nothing from the xfer case, try pulling the motor off of the TC and see if it moves when commanded. That will tell you if the motor is bad or if something in the TC is bound/broken and not allowing the motor to turn. Proceed from there are results indicate. If you are not getting any lights, it seems like things are moving just enough to satisfy the limit switches that look for movement, but that seems odd since nothing seems to really be moving.

You should only hear the sounds when going to or from 2WD. Once in 4WD, the changes are internal and you will not hear anything.

Actually, 2Hi <> A4WD you will hear two sets of sounds. A4WD <> 4HI you will hear the transfer case encoder. The way A4WD works is by moving the encoder motor back and forth to adjust clutch torque to the front propshaft. Switching to 4HI will take the encoder out of its current "adapt ready" position to the "full clutch" position. Generally, if you're stopped, the current adapt ready position should be far enough away from the full position to at least hear some noise when transferring.

Further reading: Offroad TB's NVG 226 Article

 

[C-ya]

Makes sense depending on how much noise your encoder motor makes. I can't hear mine once it switches to any 4WD mode, but I have never been underneath the truck when someone moves the switch from 4HI or A4WD to the other or done it with the engine not running.

 

[The_Roadie]

Two two different noises are trivial to separate when you do it with the engine off. Each mode transition has a distinct sound signature, and everybody should memorize what it sounds like when it's working, to help diagnose it when it fails.