From day one of purchasing my 04 Chevy silverado z71 used from the dealer I have had nothing but problems out of the 4wd. It started when I brought it home and parked it in snow and it got stuck. I had to use my wife’s mercury mariner to pull it out. How embarrassing. When it was stuck I engaged the 4wd and tried to pull out and noticed the front tires were not spinning but the back ones were going like crazy. I took it back to the dealer I bought it from several times only to be finally told there is a hole in the tcase and it is shot. $1000 later I have a rebuilt tcase with steel housings and an aftermarket oil pickup so it doesn’t make the hole again. I installed the new case and still I do not have 4wd. When I push the 4 hi button the light flashes the shift motor makes noises but then it switches back to 4 auto at which point I can switch it back to 2wd. 4 low makes a sound like it is engaged and you can feel the change in torque but you still don’t get the fronts spinning. You can go to 4 hi from 4 lo and it again acts as if it engages but still no front tire spin. I checked all of the wires when I put the new t case in. Where do I go from here?
At $1000, did the dealer install the t-case, or did you? If the dealer, take it back and have them do it right. If you did, time to have the t-case checked again.
No it was 1000 for the tcase. I put it in using the exact instructions from the chiltons manual I purchased along with a friend who used to be a transmission mechanic. Pretty sure it was done right.
I would check the vacuum hoses from the vacuum actuator (engages the front axle) back to the vacuum switch. At this age the hose ends were deteriorating on my 2000 Blazer 4wd. This article was very helpful when I was troubleshooting the 4wd system on the Blazer. If the transfer case is working a bad vacuum switch, actuator, or hose will keep the front axle from engaging. In the case of the Blazer the vacuum switch ($70) and a few hoses had to be replaced.