Slick 60's

I have a 65 F-100 with a 2 peice drive shaft. Is there a good way to check u-joints. I'm chasing a slight vibration on acceleration in 1st & 2nd gear. Mainly when I'm gett'n on it a little, which we all kinda like to do now and then.

Thanks

Willy,
The way I check U-joints is to first block a wheel on both sides so the truck can't roll. Then crawl under the truck and get a solid grasp of the driveshaft near the U-joint then try to wiggle it up and down. If there is any play in the joint, replace it. Do this at each end of the driveshaft(s) or at each U-joint. The rear U-joint at the differential gets the most flex and road crud, so it is the one that usually goes bad first.

Now I've got a question for you:
In your signature it says you've got a 1965 short bed step side F-100 with a 302 V8 in it. Obviously, the 302 isn't original. Do you know what (C-4, NP-435, ?) transmission you have in it?

Reason I ask is because I find it interesting that you've got a center carrier bearing (two driveshafts) in a short bed '65. I thought carrier bearings were only installed in long bed trucks.....Do you think the carrier bearing setup was original or was it added later?

BarnieTrk

Ive got a shirt bed. 352 with a C6 and its a 2 piece with the sleeve type. If thats what a 2 piece drive shaft is. Im having a little vibration but I dont feel it. Its more of a weird noise when Im in first and barely stepping ont he gas. It started after I lowered it. ANyway I need to get my driveshaft re done cause I know the U joints dont line up, or arent parrell with each other. Seems one shaft has rotated a little more than the other one.

Are you sure your joints are timed? If not, you could rotate them into time. Or if they are in time, you might try to rotate one spline out of time each way and see if it helps. On the larger trucks with tandem axles, some applications have to be out of time on the inter-axle driveshaft to run properly. Just a suggestion that may net a better result than what you have going now.

Fred

[quote=""Whitey Ford""]Ive got a shirt bed. 352 with a C6 and its a 2 piece with the sleeve type. If thats what a 2 piece drive shaft is.

I understand your logic, but what I'm referring to being a two-piece driveshaft is two driveshafts and a center carrier or saddle bearing[/color].
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ANyway I need to get my driveshaft re done cause I know the U joints dont line up, or arent parrell with each other. Seems one shaft has rotated a little more than the other one.

Maybe when the C6 was installed, maybe someone pulled the splined portion apart and then slipped them back together "out of phase", which will cause a vibration (this is what Fred is talking about). ASAP, I'd crawl under there (before jacking it up) and with a marker of some sort mark how far the splines slide together. Now you can block the wheels and jack it up. Drop the rear U-joint. Now try to push the longer driveshaft portion up on the spline past the mark. Note how far it goes. It should slide up another 1 to 1.75 inches on the splines. Now separate the splined portion, re-align the U-joints & slip the splines back together. Re-attach the rear U-joint. Check to make sure your driveshaft is now "back in phase". Go for a drive - your vibration may likely disappear! If you've driven it for a while "out of phase", it may have already beat the U-joints enough to screw them up and one or both U-joints may need replacement.

Im having a little vibration but I dont feel it. Its more of a weird noise when Im in first and barely stepping ont he gas. It started after I lowered it.

When you lowered your truck, it may have reduced the angle, causing the driveshaft to straighten out some and now it's too long - and possibly causing the splined ends to bottom out and may cause a vibration. As I mentioned earlier, you should have 1 to 1.75 inches of play extra spline length. If it doesn't, you likely will have to shorten the longer driveshaft accordingly.


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Just my thoughts & opinions,
BarnieTrk

Got ya. When I lowered it I made sure we kept the angle for this reason but when changing out my rear end I noticed the shaft part was pretty long but I will still check. I have all new U joints since about a year ago and I only drive it on the weekends so there isnt too many miles on them...not counting the weekends where Im working on it and not driving it or out of town so hopefully there arent crap already but will check anyway. Thanks for the info

If your pinion angle is off a little, it will also cause a vibration as you describe.