Transfer Case Encoder Motor Issues

oakridgedriver · July 20, 2011

I have a few issues unfortunately....

I noticed over the past several thousand miles, that occasionally when driving and going from a "loaded" driveline to a coasting (downhill) or light load, the transfer case would seem like it would "float" in to 4wd auto from 2wd. I thought at first I must have hit the selector by mistake, but then made concerted efforts to ensure I had it in 2wd, and yes, it was making it's own way to 4auto. It has also never been able to go in to 4wdlow, although the grinding and "servo" noises were there.

Recently I had a "service 4wd" indicator show up....I had removed the connection between a speed sensor on the top passenger side of the case and forgot to re-attach it. I pulled over to a ditch (I am much too large to simply crawl under!) reconnected the sensor and the code/light went away. All was fine for a few days, then the "service 4wd" came on again, and there is no selecting modes. The truck is driving fine in 2wd as usual. I tried all the pointers in the forums, battery/shorting leads to drain capacitors/fuses/new fluid (yes the blue fluid) all to no avail. Took it to dealer, who graciously hooked up the tech 2 n/c for me. Wouldn't show me or tell me the codes, but did clear it however it came on again immediately with the ignition being turned on. (btw, I did check out the switch, and yes it too did have a crack in one soldered post which I corrected.) Dealer did tell me that the reader said something to the effect of "reset encoder motor. Told me it would be one hour to diagnose where/what, for $118 + tax......

I have been thinking however after reading all the posts regarding the encoder motor and feel more then likely its failure is the problem, especially since it is also to "lock in" on position when it gets to where it needs to go.....if it is not "locking in" properly would that not cause the drifting in to 4auto from 2wd? and would it also cause it not to go in to 4wdlow?

In the dozens of posts I have read regarding replacing the encoder motor, they all say to ensure the transfer case shifter is in "neutral"....but, there is only one reference as to the actual position on the shifter as to where exactly "neutral" is......the one post indicates "neutral" is vertical....can anyone elaborate to confirm that? Or, does anyone have a photo of the position?

Thanks for any responses.

ujtruck · July 20, 2011

Encoder Motor Sensor Replacement

http://www.fullsizechevy.com/forum/general...ent-w-pics.html

oakridgedriver · July 20, 2011

thanks for the reply.

I read through the entire post and did find a reply on how to free up the selector shaft on the transfer case....

Wondering if when I replace the encoder motor assembly (picking up a used one from a buddy's parts truck), if I turn the transfer case shifter to match the position of the encoder motor spline, will everything default to each other? Or, will the tccm read that all is out of whack? Meaning that all posts indicate to ensure tc is in neutral, to match the position of the new encoder motor assembly.......if picking up a used one, how would a person know what position it is in when removed????? Reading posts, it is a definate no-no to activate the encoder motor without being mounted, so it seems to me I have to rotate the tc shifter to match whatever position the used encoder motor is at??

Many useful posts to read through here.....and very useful when you head to the stealer and they realize you actually have an idea of what your problems may be and how long a repair may take.....I am sure they are hating the advent of the internet!!! lol!