Driveshaft vibration

[Farmall]

Could the carrier bearing cause my truck to shake?
I have new tires, shocks and I don't think the front end is the problem (doesn't feel like it), kingpins are OK also. The steering wheel will bounce or vibrate up and down, not rock side to side. I think the steering column is just the most pronounced effect of whatever is out of line. The bounce is most pronounced at highway speeds, no load. If I hit the gas and put a little strain on the driveline, it starts to clear up and almost never does it pulling a hill.
All the universal joints seem snug but are getting replced anyhow. Could the carrier bearing cause the vibration I'm getting?

[FLATBEDFORD]

I replaced everything on my drive shaft, u-joints, center bearing, and slip joint. I couldn't believe how many vibrations went away. i don't know if this would help your exact problem, but it couldn't hurt either.

[MadMaxetc]

Sounds like you need to inspect your U-Joints. If there is slop, replace them. Carier bearing wouldn't be a bad Idea eather.

[fmartin_gila1]

Could also be a spline out of time between the front and rear shafts. Some units had a wide spline so they had to go in a matched configuration, others did not and could slide together out of time. Some of the larger trucks with tandems called for the shafts to be put in 1, 2, or 3 splines out.
Fred

[69rangerman]

If you replace the carrier bearing make sure you seat it all the way. I was lazy and thought 1/8" away from full seat was enough. Nope. Even that little bit allowed enough slop to vibrate.

When I took up the slack the vibration stopped.