Driveline Vibration

[okleven]

I have a '73 Bronco that I have installed a 3.5" lift on, rebuilt the C4 transmission, transfercase, rearend, and installed a new driveshaft in the rear. The problem I have is a rythmic vibration that is especially noticable at high speed. It cycles every 2-3 seconds. I also hear a clunk when I hit the gas and also when I let off the gas. My first thought is that it is a driveline angle issue. Any ideas?

 

[admin1]

Here are common things that could cause the vibration...

bad u-joint

loose drive shaft slip yolk

off balance drive shaft

Here are common things that could cause the clunk...

bad u-joint

loose drive shaft slip yolk

excess ring & pinion clearance

Hope that helps,

Dana

P.S. It could also be a combination of several of these items?!?

 

[davids78bronco]

okl, I'd run with your idea of the possible bad driveline angle. Is your driveline a 2-joint, or 3-joint? 2-joint being a standard driveline with a U-joint at each end. If this is what you have, then you need to make sure your rear Tcase yoke, and rear axle yoke are within 2

 

[ken75ranger]

Sounds like a ujoint. Could be the springs. The second symptom sounds like axle wrap.

 

[ted_nicolas]

Driveshaft may not be fully balanced or out of balance due to worn U-Joints.

Check for a broken off tab (in yoke, keeps u-joint centered).

If broken off of one side of yoke, it may let the u-joint be installed

slightly off center, causing unbalance. Replace Yoke.

EXTREMELY LOW BUDGET, DRIVESHAFT BALANCING TRICK:

Buy two large radiator hose clamps (new, not full of grease or dirt).

Clamp them onto u-joint close together,

with the hose clamp heads about 120

 

[Guest]

U-Joint it is! The joint that went into the transfer case yoke was sheared. I can't believe it stayed together! It had been acting like that for a while. It didn't have many miles on it. Maybe 1-2k. The Bronco hadn't been used for a while, though, so the grease could have gone bad.

 

[Broncoholics]

I'd have the driveline ballanced, new u-joints, new splines on the slip yoke and a CV on the T-case end. I added traction bars which helped big time. I never replace u-joints with 38.5" SX's! Make sure the pinion nut is tight and have good gear fluid.

 

[KROWBAR26]

Driveline angle is probably cooking the U-joint. I had the same problem when I went to a 3.5" spring lift. New Spicer U cooked in about 500 miles. Put on new rear axle with high angle pinion. Problem seems to be gone.