OT: Old Chevy Mechanic's advice needed!

"Engage 4X4" is positive, done by a shift yoke, but in "disengage mode", the shift yoke simply backs off, and a spring pushes the 4X4 shift collar setup apart when there is no "windup" or stress on the driveline.

If the driveline is under tension in 4X4, due to umatched tires, or even the fact someone has swapped gears in one axle or the other, without doing both, the shift collar won't move, and "let go" until you've driven a ways, and hit a few bumps.

Even if the tires and gear ratios match, you MAY have to drive a ways, or even back up a short distance, until the 4X4 shift collar pops out of the engaged position USUALLY accompanyed by a pretty good jerk, and clunk in the driveline.

You remind me of me. Yer memory is going. :>)

Remember on those, ya have to back up 10 feet to let 'er unhook? 'Member?

Allan

*IF* and I repeat *IF* the tires are all the same size and not putting the transfer case in a bind, I'd suspect the mode fork in the case.

They had a real bad habit of dropping the teflon wear bars off the fork and that mode collar won't move far enough to snap in and out of 4X4.

Also, they would sometimes loose the snap-ring off the rear of the mainshaft which would allow the shaft to move rearward 1/4" and mess up the shift pattern further forward.

Really doubt if the trouble lies in your hubs. Usually that trouble shows up as "no 4X4".

Seriously tho, I'd really check the tires. Even putting new tires on one end or the other and leaving the old ones on the other end would mess 'em up enough to keep them from shifting in and out of gear.

Allan

Allan