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Driveline Vibration

money pit

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My Barracuda was originally a slant six. I replaced the engine (360), 727 trans, new driveshaft, 8 3/4 rear end and heavy duty leaf springs. I have a vibration above 55 mph. I was wondering if my pinion angle is off. Where is the best place to measure the pinion angle? I watched a number of YouTube videos and they all seem to measure them differently. The vibration seems to be coming from the driveshaft or rear end. Thanks
 
Took a drive shaft of once and put back on and had a vibration.Did a rocket science move.turned the shaft 180 in the yoke. had no problem after that.Don't know why or how but it worked.
 
My Barracuda was originally a slant six. I replaced the engine (360), 727 trans, new driveshaft, 8 3/4 rear end and heavy duty leaf springs. I have a vibration above 55 mph. I was wondering if my pinion angle is off. Where is the best place to measure the pinion angle? I watched a number of YouTube videos and they all seem to measure them differently. The vibration seems to be coming from the driveshaft or rear end. Thanks
i believe the top of the axle where the pinion snubber bolts is horizontally aligned with the input shaft. unbolt the snubber and put the angle-finder on the flat.
 
This should help

Took a drive shaft of once and put back on and had a vibration.Did a rocket science move.turned the shaft 180 in the yoke. had no problem after that.Don't know why or how but it worked.
I just watched the video Chryco Psycho sent. It explains why turning your driveshaft 180 deg solved your problem. Thanks.
 
Great video, thanks. It really helped.
I checked all the angles. Everything looks okay. Maybe the engine has a vibration that's transmitted to the driveshaft. I talked to my mechanic. He said to rev the engine and see if there's a vibration. There is a vibration. He then said to put a floor jack under the oil pan with a piece of wood and slightly lift the engine. The vibration is reduced but is still there. The motor mounts are about 2 yrs old but may need to be replaced. Is there anything else I need to look for? I heard the 360 is externally balanced. Are there weights on the torque converter? Or is it balanced with the harmonic balancer? Thanks
 
If you have weights on the torque converter, do you need a flex plate with weights?
No, it’s one or the other… but be aware magnum and LA 360 balancers, flexplates, and converters are not interchangeable; they will bolt on but are balanced differently.

You can use a weighted flexplate with a neutral balance converter and vice versa.. also some aftermarket balanced flex plates like the B&M don’t have a weight but remove a piece from the other side to create an offset weight.

 
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That's what I was thinking.Also check rear end and suspension.bad tire it could be any thing wheel wheel bearing. you have to go through a process of elimination. Transmission mount motor mount,alignment.Bad u joint or needs grease,bad saddle.
 
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No, it’s one or the other… but be aware magnum and LA 360 balancers, flexplates, and converters are not interchangeable; they will bolt on but are balanced differently.

You can use a weighted flexplate with a neutral balance converter and vice versa.. also some aftermarket balanced flex plates like the B&M don’t have a weight but remove a piece from the other side to create an offset weight.

I'm going to take a look at the torque converter to see if there are weights. I think the torque converter was original to the trans. Thanks,
 
That's what I was thinking.Also check rear end and suspension.bad tire it could be any thing wheel wheel bearing. you have to go through a process of elimination. Transmission mount motor mount,alignment.Bad u joint or needs grease,bad saddle.
I've checked the pinion angle, the tires, and the motor mounts. I'm going to check the driveshaft. It's a new driveshaft and U joints. I'm going to check the torque converter to see if there are weights. Thanks
 
I checked all the angles. Everything looks okay. Maybe the engine has a vibration that's transmitted to the driveshaft. I talked to my mechanic. He said to rev the engine and see if there's a vibration. There is a vibration. He then said to put a floor jack under the oil pan with a piece of wood and slightly lift the engine. The vibration is reduced but is still there. The motor mounts are about 2 yrs old but may need to be replaced. Is there anything else I need to look for? I heard the 360 is externally balanced. Are there weights on the torque converter? Or is it balanced with the harmonic balancer? Thanks
If you have a vibration when reving the engine while parked then I don’t think it has anything to do with the driveshaft.
 
to tell if it;s in the drive train ;drive the car in second gear at the same rpm as when you have the problem also i had chrome wheel lugs that bottomed out just as the wheel tightened viberated at 90 mph
 
If you have a vibration when reving the engine while parked then I don’t think it has anything to do with the driveshaft.
I'm going to change the motor mounts and go from there.
 
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