I have a 98 5.2 4x4 auto. Sometimes when I pull out from a stop it feels like the drivetrain winds up, then kinda clunks. All u-joints are good. I had my wife shift from forward to reverse several times and each time the driveshaft would turn about 1 inch. Is there an adjustment or is the trans, t-case, or rear shot? The truck has 175,xxx miles on it. Thanks.

 

Take the load off the driveline, (jack up the rear axle.) and see if there is any side to side slop in the pinion bearings. (just grab, and shake, the driveshaft where it meets the pinion yoke.)

A bit of rotational slop is normal.

 

will do, thanks for the reply!

 

The output shaft snap ring may have come off, allowing the mainshaft to walk forward and engaging 4wd by itself.

 

Ok, I jacked up the truck and shook the pinion like suggested. I get around 1/16 of movement up an down and side to side. I guess it's time for a new rear?

 

Nah, just pull the cover, and have a look. If there isn't expensive looking stuff on the bottom of the case, just replace the pinion bearings and seals.