i own a 99 silverado rcsb z71 96xxx miles with the auto trac (push button 4wd) transfer case , im pretty sure in the drive shaft to the front differential SHOULDNT spin in 2wd (correct me if im wrong) , but i CANT get it to disengage , i replaced the switch, the tccm and the actuator on the t-case, what could it be? i know its nothing in the front differential cause if i disconnect the battery then pull the atc fuse and leave it out its in 2wd but the drive shaft still continues to spin.... im clueless as to what it could be any insite as to what it could be would surly help

 

Can you do a burnout??

or spin the back 2 tires in grass, rocks any kinda way?

 

The auto-trak transfer case will be spinning the front shaft when driving in 2wd. That's normal. In fact, if you have all 4 wheels off the ground, and put the truck into gear in 2wd, the front shaft will still spin. All normal for that transfer case.

You should be able to hold the front tires from spinning though. The front differential should be disconnected in 2wd.

 

well when i have the fuse out , its in 2wd but when i put it back in it will only go into auto 4wd and 4 hi it wont shift into 4lo or 2ws with the fuse out i can spin tires withit in its locked into 4wd

 

Might be an encoder problem. If you get any water into it, she starts acting up like a red headed step child. Also, the 4wd dash switch does go bad from time to time. I replaced 2 last year.

 

could something be binding up in the t-case?

 

As Roger stated that front shaft will always spin. The passenger side axle is actually in 2 pieces. When you engage 4wd, the motor pushes a fork that moves a coupler over both pieces of the axle making it engage. Basically when it is in 2wd, the differential spins.

In the earlier trucks there were problems with the solder in the switch. I had a similar problem with mine not wanting to go into 4wd. I removed the switch, and soldered every contact on the back of that switch in the dash. It now works perfectly. Try that and report back.

 

Is the new TCCM programmed?

 

the tccm needs programed? and the switch is a brand new dorman 4wd switch , im sure my switch is good , i did buy the tccm used could it be bad to?

 

Maybe not..I just noticed it is a '99 truck. It may just get the VIN info from the VCM. The newer ones say to program a new TCCM with the correct vehicle calibration.