Vibrates like crazy in 4WD, fine in 2WD

[woody80z28]

94 K1500 with a BW tcase swap and elec actuator conversion.

I assumed it was a CV problem, but I just got the truck in the air and don't feel any play in the CV joints. They seem to be fine.

The 4WD does work, but I cant use it above 5mph or so because it vibrates. So I'm thinking the actuator is fine. I can hear it go in and the 4WD light comes on. The front diff seems to have a fair amount of play in it, but it all spins smooth by hand.

Any other things to check out you can think of?

Thanks for any help. It's cold and snowy, so I'd love to have me some 4WD...haha

 

[Nylanderz]

Did this problem suddenly occurred? I was thinking if a previous owner has disconnected the shafts and didn't put them back together correctly it could cause imbalance in the shafts.. That could cause some nasty vibrations! I can not think of anything else that could cause those vibrations..

 

[RichLo]

If theres a lot of play in the diff, then your ring and pinion gears are worn down too much. Time to re-gear or find a low mile one at at scrap yard.

 

[woody80z28]

This problem was sudden. Fine at the beginning of the day, and suddenly vibration city.

240k on the truck, so I'm sure front ring & pinion are worn, but that is something that wouldn't happen suddenly.

 

[thz71]

U joint?

 

[98_k1500]

Or maybe slack in the splines in the front drive shaft? iv seen tons of these trucks with sloppy front shafts.

 

[SkyHighColorado]

on some lift kits you flip the front shaft and it helps with vibrations. just an idea. worked on my lift.

 

[454cid]

How did you get a Borg Warner transfercase in a half ton? Did you change anything within the last few days?

 

[poncho62]

U joint?

Yuuuuuuuppp

 

[twomanymontes]

I'm going to say U-joint as well.