Back again looking for some answers from anyone that has an idea about my vibration problems on my 54 Chevy. I changed the universal which was really in good condition. Rechecked the motor mounts including the transmission mount. Exhaust us tight off engine and not close to underbody . I have no shimmy in steering wheel at all and goes down the road nicely except for the vibration right under my feet u feel and at 45 mph. It is very noticeable with noise also so something is not right. Could it be something in the power glide transmission? Maybe the converter? I am driving this car in the city as soon it will be time to store it away and would like to find out what I need to do to it when I'm not driving it. Any suggestions will be greatly appreciated ! Thanks!
Wheel bearing possibly? My fiancé's OT Chevy cobalt had a vibration in the floor and a slight humming. Drove fine down the road and at 40mph on the dot it would start. Ended up being the driver's wheel bearing.
You can try a couple of things. First, drive thru the vibration,(if it stops), then coast and see if it returns at about the same speed. Or throw it up in neutral while it is vibrating. If it shakes on the way up and again on the way down it sounds like a flex plate/torque conv problem. If it disappears when you go to neutral, then it may be further back than the ******. I had the same problem with a car I built and the shake would go away in N, it turned out to be a ****pily balanced drive shaft. I have also seen front tires cause the same effect, check for loose lugs, bulges and so forth. Be careful.
There is probably a list of everything you have done, but missing that: Floor board vibrations tend to come up through the ch***is. Vibrations in the steering are front suspension/front tires, usually. Check the balance and roundness of all 4 tires, especially the rear tires. Check the condition of the body to frame mounts. Is there any loose tin, plastic, or rubber things that can be moved by the wind blowing under or around the car? Check the condition of the rear axle mounting locations. Does the rear axle turn nice and smooth, or is there a tight spot? Are there any missing weights on the rear brake drums? Are there any dings or small dents in the drive shaft tube? Put the car up on jackstands and have someone run it at 45 to see if the vibration is still there. You might actually be able to see what's vibrating! If the vibration stops when the car is on jackstands, its either rear tire roundness or drive line related, or its something that is wind related. Gene
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