May have found the source of my driveline vibration.

olympic

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0.030" runout on the tail end of the drive shaft! :mad: The car has had a vibration since I bought it 6 years ago but it was only noticeable at 100+MPH so I kept putting off finding the source. The worst part is I paid a shop a lot of money to shorten and rebalance this shaft when I installed the T56 Magnum a couple years ago but obviously they botched the job or just cut and welded it without checking the finished product.

Regardless, this shaft is now scrap. Any recommendations for a replacement? I'm kind of leaning towards a carbon fiber shaft from PST since I need a custom length anyways.
 

Mojo88

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Seems like you're narrowing it down, nice work.

It looks brand new under there, exceptionally clean! You obviously don't drive it much in the Canadian snowy weather, hey? :cool:
 

olympic

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Remove shaft and read runout on pinion flange.

This is what centers shaft

str-u1596_xl.jpg


I have a Strange chromoly pinion flange which has a nice flat section to measure runout. I measured less than 0.002" total. The slip yoke at the front has about 0.005" runout mostly due to the "slop" in the splines and the tailshaft of the trans.

Seems like you're narrowing it down, nice work.

It looks brand new under there, exceptionally clean! You obviously don't drive it much in the Canadian snowy weather, hey? :cool:

Thanks! I've spent a lot of time over the past couple years cleaning, polishing, powdercoating and painting the undercarriage. The car stays parked 6 months of the year for our rediculous winters...lol!
 

Mojo88

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Thanks! I've spent a lot of time over the past couple years cleaning, polishing, powdercoating and painting the undercarriage. The car stays parked 6 months of the year for our rediculous winters...lol!

Haha, oh yeah man, I know. I was born in Nova Scotia. My mother grew up on a farm in the wild Nova Scotia country, a beautiful area, I always loved visiting there. She said when she was a girl the snow drifts would be up to the tops of the telephone poles!!
 

DSG2003Mach1

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I paid a shop a lot of money to shorten and rebalance this shaft

my uncle went through this with his old 280Z. He took the drive shaft back twice and they swore it checked out. He check and replaced all kinds of shit and couldnt figure it out. He took it to a different shop and it wall out of whack, they built him a new one and it's smooth as can be. Glad you found it without spending a fortune
 

olympic

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I talked with PST and they are whipping me up a new driveshaft. 3.5" diameter .120 wall T6061-T6 DOM aluminum good up to 1000HP for a little over $400. Should be more than adequate for my needs. Carbon fiber would be nice but not worth over double the price IMO.
 

04OWwhipple

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That's super frustrating but I'm glad you finally found the culprit and it is a relatively inexpensive repair!
 

04OWwhipple

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0.030" runout on the tail end of the drive shaft! :mad: The car has had a vibration since I bought it 6 years ago but it was only noticeable at 100+MPH so I kept putting off finding the source. The worst part is I paid a shop a lot of money to shorten and rebalance this shaft when I installed the T56 Magnum a couple years ago but obviously they botched the job or just cut and welded it without checking the finished product.

Regardless, this shaft is now scrap. Any recommendations for a replacement? I'm kind of leaning towards a carbon fiber shaft from PST since I need a custom length anyways.


I'm kinda chasing my own vibration myself. I only get it at high speed and it most notable through the shift knob it buzzes crazy loud and vibrates intensely by the top of 4th gear. Does this sound similar to what your vibration is? I can feel it through the rest of the car but the shifter buzz/vibration is crazy loud.
 

hotcobra03

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I'm kinda chasing my own vibration myself. I only get it at high speed and it most notable through the shift knob it buzzes crazy loud and vibrates intensely by the top of 4th gear. Does this sound similar to what your vibration is? I can feel it through the rest of the car but the shifter buzz/vibration is crazy loud.

High speed vibrations are hard sometimes. Any thing that spins can cause it.

Tires are #1. Most balancer machine only do upto 80 if lucky.

Driveline

Transmission yoke play
Ujont play
Pinion flange play.

These will vibrate at high speed and not noticed during normal speeds

A frozen or binding joint will also cause this.

As you see he has a unbolt style pinion yoke. His if over tightened will make joint bind and burn up and shake

Flange style took away that problem
 

04OWwhipple

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H


High speed vibrations are hard sometimes. Any thing that spins can cause it.

Tires are #1. Most balancer machine only do upto 80 if lucky.

Driveline

Transmission yoke play
Ujont play
Pinion flange play.

These will vibrate at high speed and not noticed during normal speeds

A frozen or binding joint will also cause this.

As you see he has a unbolt style pinion yoke. His if over tightened will make joint bind and burn up and shake

Flange style took away that problem

Most certainly. not trying to hijack the thread but mine arose after doing an engine rebuild. I have gone through rebalanced the wheel/tires multiple times as well as switched to my 15X8 Hoosier wheels and problem still persists. Had u-joints replaced and shaft balanced and concern still persists. I starting to wonder how much I trust the driveline shop I used and wonder if they ever did indeed get it balanced.
 

hotcobra03

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Most certainly. not trying to hijack the thread but mine arose after doing an engine rebuild. I have gone through rebalanced the wheel/tires multiple times as well as switched to my 15X8 Hoosier wheels and problem still persists. Had u-joints replaced and shaft balanced and concern still persists. I starting to wonder how much I trust the driveline shop I used and wonder if they ever did indeed get it balanced.

Was flywheel or clutch changed during this.

This are balanced items.

That will cause vibrations
 

04OWwhipple

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Was flywheel or clutch changed during this.

This are balanced items.

That will cause vibrations

These are things that have crossed my mind certainly. Just a lot of work to get there. The flywheel and clutch were not changed out but I have wondered if just from taking them out and reinstalling them that possibly on is now out of balance. It is a Mcleod RXT twin disk and that's kinda what I am leaning toward at this point.
 

railroad

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On the buzz at speed, at speed put the car in neutral or push in the clutch. With the car still at speed, the driveshaft, yokes, tires and wheels will be the vib associated parts. If the vib quit, it is in the engine, clutch or trans. This can be confirmed by revving the car, while sitting still. Good luck,
 

04OWwhipple

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On the buzz at speed, at speed put the car in neutral or push in the clutch. With the car still at speed, the driveshaft, yokes, tires and wheels will be the vib associated parts. If the vib quit, it is in the engine, clutch or trans. This can be confirmed by revving the car, while sitting still. Good luck,

It still buzzes pretty good at speed even after clutching in and putting the car in neutral which makes me think the exact way as you mentioned. I'm just starting to run out of good ideas. The thing that keeps throwing me is that I didn't have this issue before taking engine, transmission, and driveshaft out to rebuild the engine which makes me discount the rear diff or cv axles. It's also hard to test as top of 4th is a pretty good MPH.
 

olympic

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I'm kinda chasing my own vibration myself. I only get it at high speed and it most notable through the shift knob it buzzes crazy loud and vibrates intensely by the top of 4th gear. Does this sound similar to what your vibration is? I can feel it through the rest of the car but the shifter buzz/vibration is crazy loud.

Mine is a loud, low sounding vibration that could be heard and felt coming through the floor boards from the middle/rear of the car. It starts at about 100 MPH and doesn't change when I push the clutch in. It gets louder when I let off the gas and coast. I never had any unusual vibration through the shifter.

In your situation, since the vibration persists even with the clutch pressed, I would keep looking at driveline components. Download the Tremec app and check your driveline angles. I like to place something flat against the crank pulley to measure the engine/trans angle. Then you have to remove the tail end of the driveshaft to measure pinion angle.

Next check for driveshaft runout at the front, middle and rear of the driveshaft as shown in my video . You'll need a dial indicator with a roller tip and magnetic base. I'm not exactly sure what the specs are but I would think under 0.010" should be OK.
 

04OWwhipple

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Mine is a loud, low sounding vibration that could be heard and felt coming through the floor boards from the middle/rear of the car. It starts at about 100 MPH and doesn't change when I push the clutch in. It gets louder when I let off the gas and coast. I never had any unusual vibration through the shifter.

In your situation, since the vibration persists even with the clutch pressed, I would keep looking at driveline components. Download the Tremec app and check your driveline angles. I like to place something flat against the crank pulley to measure the engine/trans angle. Then you have to remove the tail end of the driveshaft to measure pinion angle.

Next check for driveshaft runout at the front, middle and rear of the driveshaft as shown in my video . You'll need a dial indicator with a roller tip and magnetic base. I'm not exactly sure what the specs are but I would think under 0.010" should be OK.

Ahh. I see. Thank for the heads up on the Tremec App! I had no idea that even existed! I just downloaded it and it looks like it would be super easy to use! I'll definitely check that out sometime next week when I get a chance.

I did put poly motor mounts in when I reinstalled the engine so it possible that it raised the engine enough to throw that off I suppose.
 

railroad

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It still buzzes pretty good at speed even after clutching in and putting the car in neutral which makes me think the exact way as you mentioned. I'm just starting to run out of good ideas. The thing that keeps throwing me is that I didn't have this issue before taking engine, transmission, and driveshaft out to rebuild the engine which makes me discount the rear diff or cv axles. It's also hard to test as top of 4th is a pretty good MPH.

Mark your pinion flange and driveshaft and start clocking it, either direction. There may be some paint dots on both. These are to show run out on each. Not sure if they match or install opposite. Back to doing some work, clock the drive shaft on the yoke at 90* increments. Hopefully you will find the sweet spot. You can do this on the trans end also. If you make an improvement and want to try the front of the driveshaft, do it without changing the rear.
 

hotcobra03

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I manufactured driveshafts for 20 yrs

It’s just a basic simple thing

What you read is one thing

Working on them and seeing how the factory’s make them those numbers the other guy is seeing is close

The balancing fixture is the same as our pinion

It doesn’t matter what holes your in and turning shaft is a waste of time
And look there is 4 other holes wider. That’s for next size larger 1410 series
It’s just a chunk of metal but it is also balanced before sold

Take out shaft and have it balanced

I had no problems letting my customers watch as I do it

A one piece shaft is simple try 6piece

They are balanced together.

You can also use hose clamps on shaft
This will act just like a weight for balancing.

Add a washer

I’ve seen a dime make a difference from smooth to rattling your teeth out of your mouth
 

railroad

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I have never made a drive shaft, but Ford flew an engineer from Detroit to Alabama to get a vib out of my 99 Mustang Cobra. He put a sensor on the gear housing and ran the monitor inside the car. We drove it and he could tell me by the displayed harmonics where the issue was. We did have to replace the driveshaft, but tuned it by clocking it individually on both ends for a perfect job.
He showed me the markings on my driveshaft and pinion flange. This was the first year for Mustang IRS and the parts were supposed to be balanced better than the solid axle items. He said, unfortunately both cars went down the same assembly line, so picking up the right parts was not always done.
If you started without a vib and now have one, for the cost of clocking is a no brainer, IMO. Good luck,
 

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