I just bought a 1988 GMC stepside Z71,automatic,350. I am having trouble with the 4wd. It shifts into 4wd, but when I start to drive I can feel it pop out of 4wd and into 2wd. It does this in 4wd high and low. Sometimes I will shift into 4wd, but the front gear box won't engage. If I shift into 4wd low and high a couple of times, it will eventually kick into 4wd. Any suggestions on what cause be causing the problems? Thanks!
Josh
Josh