i resored and converted a 1972 chev c-10 long bed from manual to automatic trans ,350 3 speed. ever since then at about 45-55 miles per hour i get a vibration. the drive shaft was cut and rebalanced to fit. the front end has been alighned and the tires are new and balanced.i measured and centered the carrier bearing and lined up the u-joint yokes. but i still get the vibration. the whole truck vibrates not just the front end. any ideas would surely be appreciated. thanks.

 

Check your wheel balancing.

 

Well my 71 had a bad rear end and it felt just like that was fine all around town but up to speed it would heat up and rattle your teeth out,also is it a one piece drive line or two????

 

i would go out and get you driveshaft remeasured if you dont find out the problem. if your drive shaft is to long or to short you are going to have problems and bad vibes. when is the vibe happening??

 

Get ur wheel balancingin place, I guess it shud work

 

Here are a few things you could check to help track down the vibration:

Driveshaft Angle: Sometimes, if the driveshaft angle is off, it can cause vibrations at certain speeds. Check that the driveshaft and transmission angles are aligned properly. Adjusting the pinion angle can sometimes help.

Carrier Bearing: Even if it’s centered, make sure the carrier bearing itself isn’t worn out. A worn carrier bearing can lead to vibration throughout the truck.

U-Joints: Make sure the U-joints aren’t binding or have any play in them. Even a small issue with a U-joint can cause vibration, especially after modifying the driveshaft.

Transmission Mount: Check the transmission mount to make sure it’s secure and isn’t worn out. A loose or old mount can cause vibrations at certain speeds.

Engine and Transmission Alignment: Ensure that the engine and transmission are properly aligned after the conversion. Even small misalignments can lead to vibration.

Trying these steps might help identify what’s causing the vibration.