The Stovebolt Site Forums The Shop Area Driveline driveshaft

My 55 series 2 long wheelbase (3200) has a two piece driveshaft and lots of vibration!
After new u joints and a new center support with bearing there is still plenty of vibration. Driveshaft u joints are phased correctly. Truck is stock with only 76,000 miles. 235ci motor with 4 speed. Tires are new and balanced.
Friends have suggested that I go to a one piece driveshaft to get rid of vibes.
Has anyone done this? Is this a recommended cure for the vibration?
Thanks!

Don't go to a one piece shaft, it has two for a reason.. the length requires it.

At a drive shaft shop have each shaft checked for straightness, yokes phased correctly (welded in right to start with), and then balanced.

Grigg

Check the yoke on the rear end for tightness and check for a loose pinion bearing. Does it do it during acceleration, deceleration, or while coasting? Does it do it in all gears or in 4th only. If it has a slip joint in the rear shaft, check it. If it wasn't greased properly, it could be worn out at only 76k miles.

Hy sepp, have the shafts been checked for straightness?

Many thanks to all for your input(s).
Haven't been able to do much because the weather has been unusually rainy & cold. Spring hasn't quite gotten to Germany yet.

Been thinking of removing the two piece driveshaft and center bearing and bringing them to a specialist. They tell me that they can check the straigtness, U-joints, bearings, etc. and get the shafts back to me within a week. Sounds good, but they are a long way off and it is quite expensive.

I have given up the idea of going to a one piece shaft.

Today,I was thinking over my options and have come to the conclusion that the vibration problem first became noticeable after we rebuilt the transmision and replaced the clutch. When I checked the phasing of the U-joints, I thought I had found the problem. After correcting the phasing, the vibration diminished. BUT, it's still there! Albeit much improved.

I am now wondering if maybe I have a driveshaft balance problem. When I corrected the phasing - I may have done it incorrectly.

If I remove the rear shaft and rotate it 180°, it will still be in correct phase but maybe the balance will be better. Does this make sense? Has anybody been there??

Hy sepp, it certainly won't hurt to try that, good luck.

Once you determine whether or not the shaft is straight with a magnetic-base dial indicator, use a big hose clamp and a 1-ounce wheel weight to adjust the balance. Place the weight under, or at least near the clamp screw to concentrate the weight in one place. Move the weight around to different positions until the vibration is at a minimum, and once that position is determined, tack weld a flat washer or two onto the same position as a permanent fix. Put the check weight on one end or the other of the shaft, not in the middle. I've balanced several driveshafts that way.
Jerry