35 vibration in drive train

[CP]

Hello all,

I have not posted in quite some time. Still read forum often just haven't had the need to ask any questions since I asked many a few years ago and have learned a lot from all of your help. Evidently (no surprise) I have much more to learn.

Here's the story....

My nephew asked me last spring if he could drive my old 35 to his high school prom. I said sure. He then told me he had a problem and did not know how to drive a standard. Prom was in 3 weeks. I let him practice on my old jeep and he was ok. I told him that he must be at a complete stop to shift into first gear. Well...he broke first gear. I shipped the ****** to Mac VP for fixing. Had to ship another case, broke the cluster gear etc. etc...I installed the rebuilt ****** last week for my 300 mile (one way)voyage to Burlington VT which we make annually. I have a vibration in the drive train at 54 MPH. If I drive 59 MPH the vibration is not so bad. Never had vibration before....I prefer to drive at 55....What could it be?

I think it is the u-joint but I shipped the u-joint to mac with the ****** and he said it was fine. I have not changed anything else on car. New throwout bearing. any thoughts?

It was very difficult to pull the ****** since it sits on the frame rail very low and you need to tilt the engine to pull the ****** (after dropping rear end of coarse). The exhaust does not allow jacking enough so I had to muscle the ****** in big time. I do not know how to tell if the u-joint is good or bad... Also, I "did not" replace the pilot bearing. I "did not" resurface the flywheel. I did not change the clutch disk or pressure plate. I had no vibration previously.

Thanks for your thoughts...CP.

 

[supereal]

A good guess i that the replacement transmission is slightly out of alignment with the clutch disk and pressure plate. If it is slight, it usually will set up a periodic vibration of the type you describe. The usual fix is to put the rear wheels off the ground with good jack stands, then slightly loosen all the transmission to clutch housing bolts. Run the engine and drive train in third gear as a helper exercises the clutch pedal, then tighten a couple of bolts on each side. Shut down the engine and tighten the rest of the bolts. Lying under a running car requires precautions, of course, so be sure the vehicle is secure. Genuine Ford u-joints are tough, and can outlast the vehicle. Repros, not so much. As you didn't have the vibration before the change, it is unlikely the u-joint is bad, unless you have neglected greasing the u-joint housing.