The Stovebolt Site Forums The Shop Area The HiPo Shop Need help...Whole lotta shakin going on!

Stovebolters, Thanks for all the help thus far. Thanks to al that I took my old 50 chevy 3600 for its first drive in almost 20 years.

Problem is that when I top 30 mph the whole truck starts shaking. Now it has a 12 bolt rear end that the previous owner put in it and my guess would be improper pinion alignment but I want to know what else to check.

Of course I will also make sure the wheels/tires are balanced but any other thoughts and any ideas how i can narrow this down. Thank you Rob

Sorry you've had some problems on your maiden voyage!

You might be on the right track regarding the pinion angle etc.

It's a process of elimination as I'm sure you know,make sure the tires are not flat spotted from possibly sitting underinflated for so long,sidewall condition etc.
They may well be 'out of round' or starting to break down through age/dry rotting etc.
Jack the truck up and spin the wheels,they'll soon show if there's a problem..

Good luck.

do you have bias ply tires that sat in same spot quite awhile?

Worn out front end parts. King pins, tie rod ends, steering linkage, etc. Tires flat spotted or knotted up.

The most important question is: Is the vibration in the steering wheel, or in the body (the seat of your pants)? If it's in the wheel look to the front end or front tires, if it's in the body look to the rear end (including rear tires) or driveline. Can you drive through it, or does it get progressively worse as you go higher speeds?

It could be anything from driveline vibration, unbalanced tires, separated tire, etc., etc.

even something as simple as putting the slip yok turned on the driveshaft wrong, when the U-joint caps are misaligned, front u-joint to the back u-joint; that can cause vibrations and are tough to figure out.

all good replies...thank you. Definitely not in steering. Will let you know what I find out.

Your 3600 should have a two piece driveshaft, closed in front and open in rear. I would pull the rear wheels and open section of the driveshaft and rev engine to 2500rpm; no vibration then all is good. install driveshaft and rev, install wheels and tires and rev. Everything in the rear is now eliminated except tire trueness. We have an old spin balancer which can be used to check out all four wheels and if you have an old timey shop near you they would probably have one but if not the balance/trueness will be trial and error with driving. However, before driving jack up each wheel and set a beverage can (regular or "Lite") as close to the tire without touching and spin the tire. The trueness will be obvious and if you look closely you can also see any runout (wobble). I believe in orderly elimination rather than willy nilly.