Vibration in drivetrain

[Mopower73]

Alright so I have had this driveline vibration for a while now just wondering all the possibilities. Let me give you some info. It starts around 45mph and goes on from there. It was real bad when I had my drive shaft made. So I had it looked at 4 different times by 4 different shops and they said they got it to balance out perfect. It calmed the vibration down but it's still there. I've put shines in the rear ranging from none to 6 degrees and never made I difference. The motor and torque convertor are brand new this year. There was still a vibration last year with the old motor and torque convertor. Trans was rebuilt last year and so was rear end. So that's pretty much it just hit me up with suggestions I'm open to all.

 

[Bad Sport]

Bad tire, out of balance tire, bent wheel. Did they check the run out on the driveshaft? Just throwing things out there.

 

[67Dart273]

1---Determine FOR CERTAIN that it is in fact driveline. Run the car, stopped in neutral, and different RPM to see if the vibrations show up

2---As above, make sure you understand it is driveline and not wheel, tire, axle. The vibrations are much different and are much higher frequency. Try different wheels / tires, even if borrow some

3---What IS your pinion angle? You say you changed it, but why, and from what to what?

4---Did the balance work include the front yoke? Have you had the U joints out, or at least moved them by moving the front yoke, with the shaft out? Move the rear joint? inspect the caps inside?

5---Inspect the slip yoke in the trans, wiggle and inspect for bushing wear in the trans. Look for play and roughness in the pinion bearing. Any oil leakage from either trans or rear axle?

6---Remove rear joint from rear yoke and CAREFULLY inspect rear yoke. Are you sure you have the proper joint, and does it tightly center in the yoke? There should be "zero" play in the U joint when "set" into the yoke, before the caps are tightened down.

 

[TrailBeast]

Just another thought.
I had a pretty bad vibration in my driveline when I got the car, and just for the fun of it I removed the front yoke and reinstalled it 180 from where it was.
That did it.
Apparently a lot of people don't know that the yoke should always go back on the same as it came off. (Not turned 180 degrees)

Another little trick I have used to find out what I want to know is to mark the driveline in quarters around it and put a hose clamp around the driveline with the screw on one of the marks, then drive it and see what it does.
It will either make it worse or better.
If it is worse, then move the screw on the clamp to another of the marks and chk it again.
It takes time, but you can figure out which end is out of balance, or that it isn't the driveline at all.

 

[Supershafts]

Not nearly enough info. You said it starts around 45 and gets worse, but till what? does it get worse till 85 or 75 or go away or it just gets more violent?

You could have a issue with a axle, a bearing even the shaft still, could be at the front of the trans or back, could be the motor, could be an exhaust pulse issue.
.

 

[Mopower73]

Thanks guys for all these suggestions it helps me think but the slip yoke in the tranny is brand new and so it the yoke it the rear. But I've switched wheels and didn't change. But I've checked the pinion angle and it seems to be good. The only thing I haven't checked are the axles and I'm almost wondering on those. I'll go back through and check everything one more time to make sure everything is fine

 

[berlins]

sure it's the drivetrain and not the front end. Jack it up and set the rear axles on jack stands where tires are off the ground.(Car pointed in a direction where it won't hit anything if it falls off). Put it in drive and slowly rev it up to 70-80, still vibrate? And please don't have anyone stick any body parts under car while it's running to look around - slide a mirror or something under there.

 

[74scampy]

I have the same type of vibration that has been going on in my scamp since i bought it in 1997...but mine gets worse the faster i go up to a certain point at that point the vibration gets better until i let off the gas then the vibration comes back but way worse...the vibration i have pulsates and resinates through the whole car. The only thing that is left unchanged from 1997 is the front spindles. Please help!

 

[skep419]

I had the same problem. I put the car up on jack stands and ran it with the wheels off, without brake drums on, without axles, swapped 3rd members, changed the trans bushing, every pinion angle from -5 to +4. Had a new driveshaft built and it got way better but its still there. I bought a inexpensive shaft from Dr Diff. If I had to do it again I would buy a shaft from someone with a high speed balancer.

 

[SirDan]

I have the same type of vibration that has been going on in my scamp since i bought it in 1997...but mine gets worse the faster i go up to a certain point at that point the vibration gets better until i let off the gas then the vibration comes back but way worse...the vibration i have pulsates and resinates through the whole car. The only thing that is left unchanged from 1997 is the front spindles. Please help!

I have a car that does something like this. The bushing in the tail shaft of the trans is shot. Jack the car up support it nicely put it in neutral. Then grab the shaft and see if it wiggles at all. Make sure its in neutral and the parking brake is off otherwise your driveshaft might have a load on it and the wiggle in the tailshaft could be unnoticeable. Id actually recommend checking it in gear with the parking brake on as well. A U joint might be more noticeable that way. And since your under there you might as well check for that.

 

[Supershafts]

I have the same type of vibration that has been going on in my scamp since i bought it in 1997...but mine gets worse the faster i go up to a certain point at that point the vibration gets better until i let off the gas then the vibration comes back but way worse...the vibration i have pulsates and resinates through the whole car. The only thing that is left unchanged from 1997 is the front spindles. Please help!

Its not the front spindles

You could have a bad joint.

When you buy a shaft from non local driveline shops and use outta state places and they get shipped to you, in shipping they can be thrown around and knocked out of balance, so if you have a new shaft that doesn't mean it's still not the issue.
.