Driveshaft Pinion Angle

[rancholago]

I know this has been gone over a bunch, and I have read most of the "HOW TO" on drive line vibration.
Here is what I got going;
Removed the 3.07 gears axles housings and all (front and rear) and replaced with Axles and housings from a jeep with 3.73 gears. Installed Eaton True trac in the rear Dana 35 and Ox locker in the Dana 30. Both Drive Shafts have been rebuilt with new spicer u joints along with the front axles bearings and u joints. It has all new upper and lower control arms (stock) non adjustable. The jeep has a 2 inch lift and im running brand new 31 inch tires falken wild peak tires.
During my numerous shake down drives, I get a vibration at about 65 mph, I checked the pinion angle of the rear end vs rear drive shaft about 7 degrees from 0, Removed the front drive shaft and no more vibration.
So as it sits now the rear pinion angle is right at about 7 degrees off 0 and the front drive shaft is out of the vehicle and I have NO vibration.
So for my questions;
When I removed the front drive shaft to install all new u joints and cardan joint, the "orientation" of the drive shaft got mixed up, I now do not know exactly how it came out of the vehicle, orientation wise. How do I know the correct orientation (so that its balanced) going back in. Is this even a problem, can you install it "out of phase" and cause vibration? Are the stock drive
shafts marked in some way to insure correct reinstallation? Or is installing new upper and lower adjustable control arms the only fix for the front drive shaft... also do I need a new balanced front drive shaft ie a tom woods or some aftermarket drive shaft?
IF the reinstallation is not the problem then could the front pinion angle be the problem I havent checked to see what the angle of the front diff vs the angle of the Drive shaft is at this point.
And last, the angle of the rear drive shaft vs the pinion is 7 degrees from 0 but does not seem to be causing a problem, is it something that NEEDs to be addressed, and I am guessing new adjustable control arms are the fix for that.
sorry this is so long but thanks for any help.

 

[freedom_in_4low]

I know this has been gone over a bunch, and I have read most of the "HOW TO" on drive line vibration.
Here is what I got going;
Removed the 3.07 gears axles housings and all (front and rear) and replaced with Axles and housings from a jeep with 3.73 gears. Installed Eaton True trac in the rear Dana 35 and Ox locker in the Dana 30. Both Drive Shafts have been rebuilt with new spicer u joints along with the front axles bearings and u joints. It has all new upper and lower control arms (stock) non adjustable. The jeep has a 2 inch lift and im running brand new 31 inch tires falken wild peak tires.
During my numerous shake down drives, I get a vibration at about 65 mph, I checked the pinion angle of the rear end vs rear drive shaft about 7 degrees from 0, Removed the front drive shaft and no more vibration.
So as it sits now the rear pinion angle is right at about 7 degrees off 0 and the front drive shaft is out of the vehicle and I have NO vibration.
So for my questions;
When I removed the front drive shaft to install all new u joints and cardan joint, the "orientation" of the drive shaft got mixed up, I now do not know exactly how it came out of the vehicle, orientation wise. How do I know the correct orientation (so that its balanced) going back in. Is this even a problem, can you install it "out of phase" and cause vibration? Are the stock drive
shafts marked in some way to insure correct reinstallation? Or is installing new upper and lower adjustable control arms the only fix for the front drive shaft... also do I need a new balanced front drive shaft ie a tom woods or some aftermarket drive shaft?
IF the reinstallation is not the problem then could the front pinion angle be the problem I havent checked to see what the angle of the front diff vs the angle of the Drive shaft is at this point.
And last, the angle of the rear drive shaft vs the pinion is 7 degrees from 0 but does not seem to be causing a problem, is it something that NEEDs to be addressed, and I am guessing new adjustable control arms are the fix for that.
sorry this is so long but thanks for any help.

7 is on the high end and might start vibrating if you regear to 4.56+ but with it not vibrating now I would leave it alone.

Odds are either that the orientation of the front shaft is out or your front pinion is off by just enough that it shows up with the faster driveshaft speeds that you didn't reach before the new gear ratio.

When I rebuild a front shaft I mark the DC assembly and the shaft before I take it apart. You could flip it and try again, but if you take it to a driveshaft shop and have them balance it, then you'll know it's balanced for sure.

 

[rancholago]

Ill retry the drive shaft by flipping it over and will check the pinion angle, if i should need adjustable control arms, are there any you would recommend?

 

[freedom_in_4low]

Ill retry the drive shaft by flipping it over and will check the pinion angle, if i should need adjustable control arms, are there any you would recommend?

Usually you can get away with just adjustable uppers, and I'll never buy another set of uppers that isn't double adjustable. I'm happy with the ones I have from savvy.

 

[rancholago]

Update on my vibration problem, figured it was the front drive shaft since removing it stopped the vibration.
Best advice ever was from 4low took the drive shaft to be balanced, and another great thing was I found a shop that was really really good!
The long story short is that; two of thrust washers were missing and was causing the vibration.
These were sealed u Joints and I was unaware of the thrust washers located at the bottom of the cup. While doing the new joints in the drive shaft, I know i had a needle bearing fall over and when I removed the cup to check and insure the needle bearings were all there and in place, I must of dropped the thrust washers. To be honest I never ever heard of thrust washers in the bottom of the needle bearing cup. So it was a big learning experience and just passing it along. All of you younger guys probably know all about them but it was news to me.

 

[freedom_in_4low]

Glad you got it sorted! Yeah those thrust washers can be easy to miss. Sometimes they come out of the cup and stick to the end of the trunnion, which makes it even more important not to mix the cups around.