2004 GMC Yukon XL 1500 SLT 4Cyl8.5L - Transmissions & Drivetrains
lost reverse and sometimes drive. shifted to 4wd and problems seemed to go away. transfer case or transmission??
Wife pulled up to a light and the car wouldn't go. put it in park and waited a few minutes. shifted to drive and ran fine. While driving down the hwy the engine would rev up but the car coasted to a stop. Reverse made a whinning sound and wouldnt engage. Trailered it home. dropped transmission pan and it looked suprisingly clean after 98000 miles. Took it to mechanic to change transmission. while unloading it from trailer i put it in 4wd. reverse worked with no noises. drive worked with no problems. Drove it around the block. took out of 4wd and everything still seemed to work fine. Is the problem the transmission or the transfer case?? Or could it be a bad switch or sensor??? Can GM diagnose this on their computer??