65_Satellite
Well-Known Member
its the same driveshaft and u joint that I had when I had the automatic in the car. it didn't vibrate with the auto
At a loss with my Drivetrain Vibration
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69 Sleeper Bee
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I went and read your photo garage of the tranny swap and see you modified the auto cross member to fit the 4 speed. Looks like you did a good job but you might want to find a correct 4 speed cross member for your car and compare to your modified one. You might have the mount offset to one side a little bit. Just guessing at this point.
Frank Mopar
Well-Known Member
I just had a conversation about conversion joints with a guy who raced Mopars for years. He said they never could get the vibration out when using conversion joints.
Try moving yoke up and down at the yoke. There a bushing if it's loose it will rattle.
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INTMD8
Well-Known Member
Are your measurements and photos with weight on the axles/as it sits or on the lift at full extension?
If sitting as driven and the engine/trans are 4.5deg down and the pinion 3.8up I would expect it to be smooth.
What doesn't make sense to me, is your photo of the rear end.
It looks like 3.8deg down rather than 3.8deg up.
If the engine was 4.5 down and the pinion 3.8 up, the working angles of the u-joints should be .7 degrees averaged.
It's much more than that even just at the pinion.
If sitting as driven and the engine/trans are 4.5deg down and the pinion 3.8up I would expect it to be smooth.
What doesn't make sense to me, is your photo of the rear end.
It looks like 3.8deg down rather than 3.8deg up.
If the engine was 4.5 down and the pinion 3.8 up, the working angles of the u-joints should be .7 degrees averaged.
It's much more than that even just at the pinion.
4406bbl
Well-Known Member
If the trans is against the floor it is too high. The pics show too much angle at the rear. With the car sitting on its wheels the trans yoke angle and pinion yoke angle should be the same, or 1 degree down on the pinion....for a driver, not a race car.
66/440
Well-Known Member
Driveshaft out of phase? Had this same issue, went to an old school driveshaft shop and they told me I was out of phase. There are a bunch of youtube videos that discuss this. Easier to watch than to try to explain.
65_Satellite
Well-Known Member
That’s how it sits in the driveshaft. The c clips are on the inside. The u-joint that I took out was the same way except it was small joint to small yolk. When I got the different rear I needed the conversion joint which was small joint to big yolk.
65_Satellite
Well-Known Member
That could be a good point
69 Sleeper Bee
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The easiest thing to do is rotate the driveshaft 180 degrees just to see if this fixes the vibration.
Small pain in the *** but no $
StrokerSpanky
Well-Known Member
Could be out of phase. To check it get a cheap angle meter with a little magnet on it. Put the car on jack stands under rear-end and outboard end of front A frames by the ball joints. Turn the drive shaft to where the cross of the u joint on the pinion flange is straight up and down. Stick the magnetic angle gage to the bottom of the u joint cap. Wright the reading down. Then go to the front u joint without turning the shift and check the u joint cap there. They should be NO MORE than 4 degrees difference. I prefer 2 degrees. If it's out adjust with tapered shims at the leaf springs and by raising or lowering the tail shaft of the transmission until its within limits. Good luck.
StrokerSpanky
Well-Known Member
Oh, and only use Spicer or neapco U joints. They are the only ones I get consistant balance runs with. Others have too much play in them.
LOUIS AMSLER
Member
The 62-65 B bodies often or always had the engine mounted with the trans off center.
The trunion universal is a constant velocity joint and compensates for this. When you convert it to a slip joint
you will get a driveshaft vibration you will not be able to find. I got this from Herb McCandless himself.
I can see it on my '64 Polara. I thought it had been hit sometime until I talked with Herb. I know this is
an unpleasant truth because the tranny has to be changed. I know 2 people who never got to the bottom
of this, and sold their cars. I remember some older Cadillacs having a double uv joint that they called a cv joint.
I wonder if one of those could be put on the tranny end of your driveshaft. I also tried to move the tranny over to the center, but the front mounts
wouldn't let it. You could probable verify this with McCandless Performance
The trunion universal is a constant velocity joint and compensates for this. When you convert it to a slip joint
you will get a driveshaft vibration you will not be able to find. I got this from Herb McCandless himself.
I can see it on my '64 Polara. I thought it had been hit sometime until I talked with Herb. I know this is
an unpleasant truth because the tranny has to be changed. I know 2 people who never got to the bottom
of this, and sold their cars. I remember some older Cadillacs having a double uv joint that they called a cv joint.
I wonder if one of those could be put on the tranny end of your driveshaft. I also tried to move the tranny over to the center, but the front mounts
wouldn't let it. You could probable verify this with McCandless Performance
66/440
Well-Known Member
I have a '59 Cadillac with a 2 piece drive shaft. It is a real PITA to get the center carrier aligned with the transmission AND the differential. I have engine / transmission swapped many A & B bodies over the last 50 years and have never experienced the kind of issue you are facing. A few times I have had to loosen everything (engine, transmission mounts and crossmember) taken the weight off of the drive train with a hoist and just kinda wiggled it all around to get a better alignment. Trunnion's on drive shafts wasn't Mopars greatest invention.
Sixpactogo
Well-Known Member
Just looked at this thread. In your initial pictures (post #1) the 4th picture shows you have Two 2 degree shims.
First problem is you have them in the wrong position. They need to go in from the front to raise the pinion up to 3.8 degrees.
Second problem is they need to go all the way under the perch not the way you have them installed. I think you are confused with the "pinion up" claim. Your last picture in post 1 shows your pinion arrow up but in fact it is down. I think if you get those shims turned around and in the proper place with the pinion nose up you will see a big improvement.
Another thing I would do is since you have the large yoke on your pinion, I would have a drive shaft builder cut off that small yoke on the driveshaft and put the big one on since that could be causing some of your problems also.
First problem is you have them in the wrong position. They need to go in from the front to raise the pinion up to 3.8 degrees.
Second problem is they need to go all the way under the perch not the way you have them installed. I think you are confused with the "pinion up" claim. Your last picture in post 1 shows your pinion arrow up but in fact it is down. I think if you get those shims turned around and in the proper place with the pinion nose up you will see a big improvement.
Another thing I would do is since you have the large yoke on your pinion, I would have a drive shaft builder cut off that small yoke on the driveshaft and put the big one on since that could be causing some of your problems also.
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Exactly what I was thinking.
Being that the 65 cars were built with a slip yoke from the factory. Also the engine location is the same up to 1970. What leads you to believe this? I've chased a 4 speed vibration as well. Down to the last two items. A; the output shaft of the trans is slightly bent from a previous failure. B; The driveshaft is out of phase. Been thru pinion angle, U joints, yoke, driveshaft runout, driveshaft balancing, different center section, axle shafts, trans mount, extension housing, extension housing bushing. For sure it's driveshaft speed. Clutch disengaged, or in neutral still vibrates. I'm going to borrow a driveshaft from a friends car and see what happens.
Doug
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