Driveline vibration!!! I need help!

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You didn't answer the question about the source for the mounts. If they are new and are not USA made they are likely your problem, especially the trans mount.
 
Take the drive shaft out and check the joints for any binding, then take it to another machine shop, and have them spin it up,, that vibration that comes and goes at 50-60 mph is classic u-joint symptom,, but if shaft was accidentally contacted by hoist, (I've done it), could be bent,.. but it sure has driveshaft symptoms, and machine shops make errors too,, believe me,, they dooo...
 
It's in the driveline by what you describe. I think you'll find if you are the heavy footed type, that it will go away when you get to 75 or so, and probably come back arund 125. What exactly is the poinion angle? You said you checked it, but you didnt say what you had. I'm guessing the car has some rake to it... Super stock springs too? Also check the play in the slip yoke and trans tailshaft. There should be only about 1" of polished yoke showing with the car sitting on it's tires, with you sitting in it. Pinion angle or slop in the yoke can do what you describe. I'd also second the "have the rear tires dynamic balanced by a real tire shop. This would not be a Town Fair or Goodyear... A real tire/alignment shop...
 
Many driveshaft shops are notoriously sloppy when it comes to welding the yokes on the tube, that's why they have to balance them. I make my own shafts in a lathe and install the yoke so there is no runout at four points perpendicular and horizontal to the u joint cross. I've never had to have a driveshaft balanced when doing it like this.

It sounds like your shaft just has too much runout.
 
moper said:
It's in the driveline by what you describe. I think you'll find if you are the heavy footed type, that it will go away when you get to 75 or so, and probably come back arund 125. What exactly is the poinion angle? You said you checked it, but you didnt say what you had. I'm guessing the car has some rake to it... Super stock springs too? Also check the play in the slip yoke and trans tailshaft. There should be only about 1" of polished yoke showing with the car sitting on it's tires, with you sitting in it. Pinion angle or slop in the yoke can do what you describe. I'd also second the "have the rear tires dynamic balanced by a real tire shop. This would not be a Town Fair or Goodyear... A real tire/alignment shop...
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Guitar Jones said:
Many driveshaft shops are notoriously sloppy when it comes to welding the yokes on the tube, that's why they have to balance them. I make my own shafts in a lathe and install the yoke so there is no runout at four points perpendicular and horizontal to the u joint cross. I've never had to have a driveshaft balanced when doing it like this.

It sounds like your shaft just has too much runout.
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816_yepIcon.jpg
 
Guitar Jones said:
Many driveshaft shops are notoriously sloppy when it comes to welding the yokes on the tube, that's why they have to balance them. I make my own shafts in a lathe and install the yoke so there is no runout at four points perpendicular and horizontal to the u joint cross. I've never had to have a driveshaft balanced when doing it like this.

It sounds like your shaft just has too much runout.
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I'd agree with this too. My shop (an old super experienced guy) does either the same thing or very similar, and I don't think I've ever seen more than a peice the diameter of a pencil eraser if anything on his shafts.
 
I'm pretty sure this is not wheel/tire issue. If it is, the car will vibrate at any speed.

Its also not engine/trans mount, because vibrate does not relate to engine RPM.

I'm 100% this is driveshaft problem: 40% driveshaft out of balance. 60% driveshaft too long. I bet if you keep driving over 55mph, the vibration will not go away.

If I were you, I will put the new shorter driveshaft or have the shop shortern the current driveshaft.

KAMSGTS440 said:
demon seed: yes this vibration is speed related...
1970pavalient: no play in the driveshaft
67dart273: this drive shaft was taken to a driveshaft shop...this is all they do...it was lengthened with a new tube rebalanced and new u joints installed, the extended length was determined by them and the measurement was taken with the axle tubes supported with jackstands, pinion angle was measured and was within specs as determiined by the driveshaft company
purplehase:new tires and wheels balance ok
oktire: this vibration is coming from the midpoint to tail end of the car
GUP:new tyranny mounts and new motor mounts but i will check bolts for tightness
moper:this vibration only happens aroun d 55 mph and is not rpm related i feel it in the seat and in the center console and it does get worse...starts at 50-55 gets a little worse arouind 60...it seems as though i can feather the gas pedal and get it to smooth out a little bit... i havnt tried slipping it into neutral at the vibration speed ...i will try that... when I shift down to second gear and at same rpm there is no vibration...also when in neutral sitting in driveway at same rpm... no vibration....

i hope this info helps...i'm at my wits end with this problem
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Originally Posted by aka474
I'm pretty sure this is not wheel/tire issue. If it is, the car will vibrate at any speed.


Purple Haze said:
No it will not.
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Anybody that's ever owned an older 4x4 knows this. You'll be cruising along, 35, 38, 39.874045830 mph and hit that "magic harmonic" when those great big off road tires just take off into a wild-assed shimmey-shake
 
Yep, and not only 4x4 with big *** tires. Just because you got new tires and wheels and were just balanced doesn't mean that the guy who balanced them knew WTF he was doing. Or gave a shiat.
 
well did some more test driving... the vibration seems to smooth out @ 70+ decelerate from that speed and vibration starts...driving in 2nd gear @same speed where vibration is in 3rd gear, no vibration...drive in 2nd @ RPM where 3rd has vibration, no vibration in 2nd...drive car to speed where it vibrates in 3rd then dump it in to neutral keeping engine rpm up, there is no vibration as well in deceleration from that point...the only scenerio I see where there is a vibration is in 3rd gear starting @50-55 and smoothing out @70+...one other thing the vibration is the worse under deceleration from 65 down


oh and the tires were bought new 6-8 mos ago...we assumed we had a wheel that wasnt true so last week I tried new wheels...still have the vibration....if it was a tire/wheel problem it wouldnt matter if the car was in 3rd or second...this vibration only happens in 3rd gear
 
67Dart273 said:
Originally Posted by aka474
I'm pretty sure this is not wheel/tire issue. If it is, the car will vibrate at any speed.




Anybody that's ever owned an older 4x4 knows this. You'll be cruising along, 35, 38, 39.874045830 mph and hit that "magic harmonic" when those great big off road tires just take off into a wild-assed shimmey-shake
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Not just older 4X4.....We call it "death wobbles" in lifted jeep world. It goes from a small shimmy to an all out uncontrollable shake that threatens to rip the vehicle apart. Only way to get it to stop is slam the brakes on and get the speed off as fast as possible.

This problem he is describing here is definately drive train related, everything recommended to check above is valid. Just as in jeep world a systematic check piece by piece will generally allow you to find the issues and correct them.
Here is a good read. It is talking about jeeps but it applies to all.

http://www.dirtroadmagazine.com/articleb.htm
 
yooper822 said:
Not just older 4X4.....We call it "death wobbles" in lifted jeep world. It goes from a small shimmy to an all out uncontrollable shake that threatens to rip the vehicle apart. Only way to get it to stop is slam the brakes on and get the speed off as fast as possible.

This problem he is describing here is definately drive train related, everything recommended to check above is valid. Just as in jeep world a systematic check piece by piece will generally allow you to find the issues and correct them.
Here is a good read. It is talking about jeeps but it applies to all.

http://www.dirtroadmagazine.com/articleb.htm
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if it was a tire/wheel problem, it wouldnt matter whether u were in 3rd or 2nd,,,it would vibrate...this problem only exists in 3rd gear:puke:
 
KAMSGTS440 said:
well did some more test driving... the vibration seems to smooth out @ 70+ decelerate from that speed and vibration starts...driving in 2nd gear @same speed where vibration is in 3rd gear, no vibration...drive in 2nd @ RPM where 3rd has vibration, no vibration in 2nd...drive car to speed where it vibrates in 3rd then dump it in to neutral keeping engine rpm up, there is no vibration as well in deceleration from that point...the only scenerio I see where there is a vibration is in 3rd gear starting @50-55 and smoothing out @70+...one other thing the vibration is the worse under deceleration from 65 down


oh and the tires were bought new 6-8 mos ago...we assumed we had a wheel that wasnt true so last week I tried new wheels...still have the vibration....les schwab has a machine that will test ur tire whel combo for trueness and can tell if the tire OR wheel is causing the problem...I think I might make the 30 mile trip...
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OK, well from the sound of this it's in your trans. If it were your drive shaft it would still vibrate when you put it in neutral.
 
Check the engine and transmission mounts, and what were the results of the pinion angle bit? What kind of exhaust is on the car and where are the hangers for it?
Rotating parts all create harmonics. Normally things are set up to limit that, but when you start changing parts, or moving them around, you can alter the frequency of them. If ti comes and goes, and doesn't do it when the drivetrain is loaded (either at cruise because power is being applied to maintain speed, or from accelerating or decelerating) it's shaking. I don't think it's tires or the shaft itself. I think it's the relationship between the angles that's doing it.
 
Check to insure that the Universal caps are held secure and are centered in the yoke on each end. On my drive shaft, I had to use 2 C-clips on each Cap, otherwise the caps would slide out to the C-clip, allowing the Universal to slide to one edge or the other. It was intermittant, but followed the same problem you are experiencing. Also be sure to inspect the Universals for wear. My 66 cuda completly lost all of the needle bearing on one corner, causing it to vibrate as well.
 
Not sure if you got this fixed, But as mentioned earlier in the thread, I had the same problem. I upgraded my torque converter from an 11" to a 9.5" a few weeks ago and my vibration went away. The 11" was brand new when I put it in but it was a cheap ACC boss Hog 2800-3200 unit ($300). i bought a 9.5" PTC 3600 (was made for a 440 so might be 3800 on my setup) and not only did the vibration go away, It was like I added a 50 shot of NOS to the car. It's Awesome. Hope this helps.
 
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