Moparts

U-joints that vibrate?

Posted By: 74RALLYE

U-joints that vibrate? - 12/23/14 02:27 AM

I have a new rear u-joint in a 74 B-body that may be the cause of a new vibration. The frequency of the vibration tells me it's comming from the drive shaft. I swapped in a known-to-be-good hogs head at the same time I replaced the u-joint. This was after the yoke broke.
A Mopar friend said to use only Dana-Spicer u-joints to avoid the occasional bad u-joint that other manufacturers seem to produce. The suspect u-joint is a Precision 347(made in USA). How common are out of the box defects?
Posted By: RapidRobert

Re: U-joints that vibrate? - 12/23/14 02:37 AM

Any possibility when the yoke broke it tweaked the shaft? I'd pull it & move the front yoke thru both planes of travel and the rear one thru it's plane of travel & all should be smooth. Other than that I'd have the shaft checked/balanced but first share what happened with the yoke failure
Posted By: 74RALLYE

Re: U-joints that vibrate? - 12/23/14 03:45 AM

I swapped in a 4sp and rebuilt the 440. The 1st test drive didn't go well. I had my Edelbrock 800, complete with it's off idle dead spot, forcing me to rev it to take off.
I hope it's not the drive shaft. The breakage occurred at low speed with high torque.
Posted By: buildanother

Re: U-joints that vibrate? - 12/23/14 04:00 AM

All 4 "C" clips in place on each joint?
Posted By: Grizzly

Re: U-joints that vibrate? - 12/23/14 04:45 AM

Quote:

.............
A Mopar friend said to use only Dana-Spicer u-joints to avoid the occasional bad u-joint that other manufacturers seem to produce. The suspect u-joint is a Precision 347(made in USA). How common are out of the box defects?



Your Friend is right. It took me a while to figure it out, but I will never run jobber greasables again. Nothing but problems no matter how often you grease them.

All Spicer from now on.
Posted By: pro-streeter

Re: U-joints that vibrate? - 12/23/14 05:18 AM

I had a vibration too. Traced it to the pinion angle. After correcting the angle the vibration was gone. After swapping in the 4 speed you should check the pinion angle at the differential. The Mopar performance spec is 5 to 10 degrees nose down at the differential with manual transmission. I set my Road Runner 4 speed car at 5 degrees nose down. IMO 5 degrees is plenty for street use and the occasional trip to the track.

The recommended drive shaft runout should not exceed .015" this measurement should be checked at both ends and the center. This can be done with a dial indicator and magnetic base.

The balance should be .3 in oz at both ends of the drive shaft.
Posted By: rowin4

Re: U-joints that vibrate? - 12/23/14 06:14 AM

You say you broke the yoke? Do you mean the straps on the yoke ? I have never in close to 50 years of racing seen anyone "BREAK" a yoke. I have seen strap bolts break and of course spit out the u-joint. When this happens sometimes the yoke will spread causing the joint to not properly seat in the yoke causing the drive shaft to vibrate. What's the total story. Did you replace the yoke? or just the straps?

Posted By: 74RALLYE

Re: U-joints that vibrate? - 12/23/14 06:35 AM

All C clips are in place. I rotated the drive shaft 180 degrees last weekend and it got a little worse.

It sheered the whole ear off. I swapped the chunk w/yoke out and replaced the straps.

Attached picture 8371086-IMG_s2685.jpg
Posted By: RapidRobert

Re: U-joints that vibrate? - 12/23/14 06:46 AM

Quote:

It sheered the whole ear off.

replace the shaft (or have a shop check straightness & see if it can be taken care of)
Posted By: elmor353

Re: U-joints that vibrate? - 12/23/14 08:35 AM

In 1973 I had a 63 300 with a 413/auto and broke the rear yoke in half while power braking in my buddy's driveway.
Posted By: moper

Re: U-joints that vibrate? - 12/23/14 02:43 PM

Quote:

[
Your Friend is right. It took me a while to figure it out, but I will never run jobber greasables again. Nothing but problems no matter how often you grease them.

All Spicer from now on.




x2. The tolerances stack up and even brand new joints will have too much slop once installed. It's slop between the joint's trunion and the needles/caps. Usually enough to see it if you have a good light under there.
Posted By: scratchnfotraction

Re: U-joints that vibrate? - 12/23/14 04:04 PM

make sure the caps are not spinning in the yoke.

and the yokes are not spred/worn out
Posted By: moparjim79

Re: U-joints that vibrate? - 12/23/14 06:34 PM

Broke the pinion yoke on my 72 charger. 318 4 bbl w 3.91s. Downshifted to first doing 30 at full throttle. It was gnarly.
Posted By: poorboy

Re: U-joints that vibrate? - 12/24/14 12:22 AM

Quote:

You say you broke the yoke? Do you mean the straps on the yoke ? I have never in close to 50 years of racing seen anyone "BREAK" a yoke. I have seen strap bolts break and of course spit out the u-joint. When this happens sometimes the yoke will spread causing the joint to not properly seat in the yoke causing the drive shaft to vibrate. What's the total story. Did you replace the yoke? or just the straps?





You obviously were not trying hard enough! I think, through the years, I've managed to break just about everything under a car. Some stuff was more difficult then other stuff, and some of it broke and it wasn't even fun.

As I've gotten older, I break a lot less stuff, mainly because I'm too lazy and too cheap to keep replacing stuff.

To the op, if you broke the pinion yoke, the driveshaft is in question, as is the pinion shaft in the rear axle. When you changed the yoke, you didn't mess up the ring & pinion setting, did you? Gene
Posted By: rowin4

Re: U-joints that vibrate? - 12/24/14 02:03 AM

Quote:

All C clips are in place. I rotated the drive shaft 180 degrees last weekend and it got a little worse.

It sheered the whole ear off. I swapped the chunk w/yoke out and replaced the straps.




Ok, you changed out the chunk. If you swapped ends on the drive shaft and it got worse , I would think the drive shaft is bent some.
Posted By: mopar346

Re: U-joints that vibrate? - 12/24/14 02:33 AM

Quote:

Quote:

All C clips are in place. I rotated the drive shaft 180 degrees last weekend and it got a little worse.

It sheered the whole ear off. I swapped the chunk w/yoke out and replaced the straps.




Ok, you changed out the chunk. If you swapped ends on the drive shaft and it got worse , I would think the drive shaft is bent some.



I take it he rotated the shaft 180* in the yoke not swapped ends.
Posted By: StrkrDart69

Re: U-joints that vibrate? - 12/24/14 03:09 AM

Hogs head?? Never heard that before.
Posted By: scratchnfotraction

Re: U-joints that vibrate? - 12/24/14 03:53 AM

might have to check your sprag(over running clutch) in the trans to make sure it did not get damaged with the drive line failure.

if the shaft came out of the yoke under power that shaft is BENT FOR SURE.

Posted By: 74RALLYE

Re: U-joints that vibrate? - 12/24/14 05:37 PM

First I'm going to try a spicer u-joint ASAP. I hope it's not the drive shaft. I replaced it 2 years ago after another u-joint failure that happened shifting from 2nd to drive at 94mph with the automatic. That was scary.

Hogs head may be the Ford word for "The chunk."
Posted By: RTDaddy

Re: U-joints that vibrate? - 12/24/14 08:19 PM

Quote:

First I'm going to try a spicer u-joint ASAP. I hope it's not the drive shaft. I replaced it 2 years ago after another u-joint failure that happened shifting from 2nd to drive at 94mph with the automatic. That was scary.

Hogs head may be the Ford word for "The chunk."



For those of you who may not know, 74Rallye is a former Ford guy. "Forgive him, he knew not what he did." Obviously, he has returned "from the dark side."

"IF YOU'RE UNDER CONTROL, YOU AIN'T GOING FAST ENOUGH."
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