The Stovebolt Site Forums The Shop Area Engine Shop pinion angle/driveshaft

I just called tom woods driveshafts to ask about an estimate for a driveshaft on my 63 c10. I explained to him that I've been having a vibration whenever im in the throttle between about 20-40 mph. He then explained to me that a vibration like that probably has more to do with the pinion angle being misaligned and putting in a new driveshaft will more than likely make the vibration more noticeable. I know theres a tool you can use to measure the angles, but I'm not sure how to go about actually adjusting it. I know theres shims youre supposed to use and thats about it. I did some searching on the site and found a lot of links in topics that looked good but they were posted years ago and no longer work. Anyway, if someone could give me a rundown on it id really appreciate it. If it makes any difference, I'm running a coil spring suspension. Thanks.

What have you changed on this truck? Pinion angles do not change themselves.

I havent changed anything. I just bought it about 2 years ago and the only suspension work I've done is new shocks all around and new rear springs. The only thing I can think of is that one of the previous owners did something and got it out of whack because the vibration has been there since i bought it.

Does it have a 2-piece driveshaft? The carrier bearing can be shimmed to change the angle of the center universal joint and the junction of the two driveshafts. Sometimes just a fraction of an inch of change in the position of the carrier bearing makes a big difference.
Jerry

Patrick,

Before you spend money on something you're not sure of, I would four wheel the rig on jack stands, put it in gear and lay back on my creeper and watch the drive train.

You can even have a 'driver' bring it up to the offending speed and see if a bent drive line is a possibility.

Stuart

This tech tip has some great info and links in it, I would suggest you read through it, then bring on the questions.
http://www.stovebolt.com/techtips/driveline_setup.html

Grigg

Have you checked the universals and pinion for play?

hotrod lincoln - no i have a one piece driveshaft

automarc - sounds like a good idea ill try it when i get back to MD in 2 weeks.

grigg - i skimmed over that link real quick it looks good ill definitely read it more in depth

tuckernix - no i havent checked them for play. should i jsut see if theyre loose or is there a way to properly check for that?

Generallly you can jack it up and grab it near the joints and just try to wiggle it....or, like someone suggested, have someone get in the truck and watch the driveshaft as its put into gear, then have them put it in reverse and see if it is moving around any. Just from the conversation I wouldn't go messing with the pinion angle just yet. To many other things can cause what your talking about.....I've even seen the little weights come off a drive shaft causing a little vibration.
Also, do not rule out tires, rims ect.
Do a little checking and let us know what you find out.

The angle of the u-joints can be checked in a matter of minutes, so I say go ahead and check them, then you can also check for worn parts, as that never hurts.

The angles can be found with a protractor head with a level in it, like comes in a good combination square set. Or can use an angle finder, the roundish one with a magnetic base and a pendulum. Read the manuals in the tech tip for all the details and reasons, but you will be looking for the transmission output shaft and the pinion to have parallel centerlines.

Sometimes people will say the "pinion angle" should be so many degrees and give a number, but there is no right or wrong pinion angle without knowing the angles of the other parts. If it is right or not is 100% dependent on its relationship to the other components of the driveline.

Grigg

okay cool. thanks everyone. i will definitely be trying all of these things when i go home in a few weeks.

someone had said earlier that a good way to see if something in the driveline was off was to raise the truck up and put it into gear and watch as the driveshaft turns, however, i heard this is really dangerous to do? what are the dangers of putting it up on a car lift and putting it into gear?

It's not so dangerous to put it on a lift and do it, but a jack, or a block of wood, or even jack stands is somewhat more risky.
If you do put it on a lift and run it obviously don't stick your hands or self in the way of anything moving. Also don't do anything fast, don't accelerate hard, and don't brake hard, as it can move the truck.

I think I would hold off on that method till after you check the angles and feel for loose parts by hand, if that does not reveal any possible problems, and you still have a problem, then try running it in the air.

Grigg

oh okay, gotcha. Thanks for the advice.