Full Time noise

[tonyb]

Bought the 78 with a drivetrain noise, still doing it but it is starting to bother me. It is a 78 3/4 ton 350 Full time 4 wheel drive. noise is under power coming from somewhere up front or middle, Wheel bearings are good. Big money to fix? Any thoughts?

[gunrac]

Is it a whine, clicking, clunk, is there vibration?

[Irish_Alley]

could be a few things, could even be timing

[zieg85]

First thought front axle u-joints, second thought is the slip yoke on the front drive shaft.  So many possibilities. 

[tonyb]

Whine like wheel bearing but only under power and doesn't change when turning. Front differential?

[Irish_Alley]

take front driveshaft out and lock the t case. unlock the front hubs or remove if auto and tape a bag over the hubs. this will isolate the front from the rear.

[tonyb]

Thanks