I've been chasing a vibration forever. It's definately past the transmission. I've had this driveshaft custom made locally at a driveshaft shop many years ago. Took it back to them after a few years to re-check and they did. Said it was great....no charge. Put the Dana in, and took it to them to have them shorten it and re-balance and expressed to them, that it needs to be perfect, as I've had vibration issues before the Dana converstion.

They shortened it nice and it's good to go.
Still have vibrations above 50mph.

So last night I put a dial indicator on my floorboard and read the runout on the shaft (should have done this years ago!). Well it's out of round by .030" or so. Same off-center at all spots on the driveshaft. It's like the tube was not perfectly centered on the Ends when it was welded.

Is this too much runout? What to do here? I don't want to just throw money at it and not be any better off.

Have you read my post on my demon vibrations??

I just had a "custom" shaft made and its got the same problems. Mine was/is .072 out. Mine is really bad, and I can hardly see straight above 50, but 70-110 was almost scary. Its back to their shop getting fixed.
https://board.moparts.org/ubbthreads/show...e=7#Post5413616
Kasey

I thought mine was bad! I've always had this anoying vibration above 50mph. Not violent, but anoying. I've re-bubble balanced my tires, swapped tires / wheels, changed brake drums, checked runout on aftermarket axles, center hub register on brake drums,........

My dial indicator sweeps a total of .030" to .034". SO it's out of round. Would take moving it around .015" on the ends to get it back in the perfect center.

Is this too far out? I think so, but let's hear what is an acceptable range.

I can tell you that our new trucks, and rear wheel drive cars at the dealership call for 0 run out.

I guess that .005 would be acceptable from bushing wear, and u-joint slop between the caps.

Kasey

Take it to greensburg driveline... he can fix it. He did two of mine, experienced mopar guy too.

Thanks, I'll keep that place in mind.

I'm going to a local place (1 mile from my house) to have them check out the current driveshaft and see what they say.

Anybody else have any input on this? This drive shaft is a little less than 3" in diameter....not much.

Should it be upgraded to 3.5" or something?

Is it bent or made wrong? Did you indicate the whole shaft? Where is it running out, all over or just at one end or just the middle?

I say it's made wrong. It is out about the same amount all along the driveshaft, pretty darn evenly. It's not like it's out at the trans end and not at the rearend. It's not just out in the middle or something. It's out the same amount from front to back.

Talked to a local drive shaft guy and he measured it. Way out. Around .025" out at the worst point. Said the shaft was made wrong. Made out of round!...Like I thought.

Tube is 3" but super thick heavy wall stuff. He said there would be no way to properly balance this thing...and it is definately going to cause a vibration.

After dealing with him on making me up a new shaft, he pushed me to getting an aluminum one. But at the end, he can't really make what I want that would hook up to my pinion yoke (1330 Big Cap for a Dana 60).

So I called Dynotech and they are making me up a 3.5" aluminum one with 1350 slip yoke and joint up front and a 1330 big cap out back. Now I just have to wait for it.

By the way,...Don't get a drive shaft from Drive Line Services in Pittsburgh (Lawrenceville area). That's where I got this old one and took it back 3 times to check and shorten at times. I told them to check it out and I'll have them build me a new one, if it's out. Pretty sad that they can't even tell that it's out! Bad Bad Bad.

Don't use them.

What ever happened with this Larry? I just did a trans/converter and thought I'd do the right thing and replace the front yoke to insure against leaks. Upon driving, I noticed vibration that I never had before, and thats with my 2.94s. My runout was .022". I swapped the yoke back to the original and it was .012", go figure. It was a brand new Mopar yoke. I have had excellent experiences with Dynotech. They were the OE supplier to GM for the Typhoons and Cyclones...

I must have replied to some other post about this, but I did report back to this issue.

Anyways,...yes, I got my Dynotech aluminum drive shaft with new 1350 yoke and new solid u-joints. It's light and you can just tell the quality is off the charts. Extremely nice piece.

Put it in the car, and no vibrations at all! None! Unbelievable that I had been chasing vibrations forever and even after that old driveshaft was "checked", it was clearly the problem.

Good to hear. I am always impressed with there pieces. Some guys in the business just get it, they obviously do.