Lesson learned on u-joints and driveline vibration

[RBeckman]

After I put in the 5 speed I still had the vibration at 50 to 70 that I've had for over 10 years and always blamed it on the 41 year old drive shaft even thou I kept going thru u-joints.

Well after 700 miles on the new transmission I had u-joint noise again and got under the car and could move the drive shaft up and down on the yoke axis. I started doing some measurements on the yoke and u-joint and see about a 5 thousands difference, I then went and bought a new u-joint and still the same difference. I then called a drive line shop and gave them the dimensions I was seeing on the yoke and they told me that it was worn and I needed a new one. (I was having a hard time believing that these things could wear out). I ordered a new one for about $80 and installed it and wow what difference it makes. I took it up to about 90 mph (2600 rpm) and no vibration. Also...wheel hop is greatly reduced (that was the fun test).

Just thought I would post this for anyone that does a search for vibration that it is a thing to look at.

The measurements I was getting on the old yoke were 3.275 and the new one was about 3.230

[Bowtie-Bri]

Hey Ric,
I know exactly what your talking about.
I have a vibration in at around 70mph. I replaced the trans with a 700r4.
I also had a different driveshaft cut and replaced the u-joints. I still had the vibration. Once I get the car back on the road, I'm planning to do a gear change from a 3:31 to 3:73. I think I might just replace the yoke on the rearend and hopefully my vibration will be gone. ;)