My son and I are rebuilding a '77 F150 4wd automatic, our first, and we would like to know what the proper procedure is for engaging the 4wd. The truck has manual locking hubs.

 

Turn the hubs to "Lock" position, then shift to "4H" when you need 4WD. At least on my '95, shifting between 2H and 4H can be done up to 50 mph, according to the manual. Hubs can be left locked, but normally, you do not want to have 4WD engaged on pavement with good traction as it can put some unnecessary stress on the driveline.

 

Yup, in and out of 4H w/the hubs locked while moving.Into and out of 4L only when stopped.

Brian