I’ve been chasing a vibration down for a while now. A bit of background. I have a 1951 3100 with a 1954 235 and a sm420 transmission. I put a new clutch disc and pressure plate on. It also has a 1957 chevy truck open rear end that I changed from 390 gears to 338 gears as well as rebuilt with all new seals and bearings. I had a new driveshaft made and balanced. The symptoms I have are as follows:
1. When starting in 1st gear ( not granny) it seems fine. Shifting to 2nd is ok until I pick up speed and then just a slight vibration. Shifting to 3d is a little vibration until it gains some speed and it vibrates pretty strongly.
2. I live in a house that is up a road 2.5 miles from town and is higher in elevation. When I go to town ( downhill) the vibration is not as bad. Coming back uphill when the engine is under load, the vibration is more noticeable, especially in 3d.
3. Coming uphill with curves in the road, I notice the vibration is less when I’m taking a left curve, more when I take a right hand curve.
4. When I put the clutch in, the vibration stops. When I rev the engine with the clutch in, it seems smooth and no vibration.
I am looking for guidance to solve this issue. I know the collective knowledge here at Stovebolt and would appreciate any and all help. What am I missing?
