Hot Rods rear diff noise

ok i removed the trash bars or solid traction bars. rode to tight and rough. got all back together. ride tested. got on it a little. get a vibration and rumble out of rear of car. these bar were mount to u/bolts and clamped tight on front of spring. could this have taken the arch out and when i got on it the resr diff might be dipping? 40 ford leaf spring rear. also leaning a inch on l side.

 

Does the pinion angle match the rear of the transmission shaft angle? At ride height.

 

how tall are the lowering blocks?

 

did not add any lowering blocks going to crawl under and see what angle is today

 

so do i pick a flat spot on diff and on trans. muncie 4 speed. 62 gm rear end

 

Measure vertically at tail housing at out put end and vertically at rear end pinion.

Example

 

I've found it easiest to measure on the u-joint caps. I use a Snap-On socket that just fits the cap. I've already checked the socket for being square. Go from cap at trans to shaft and then shaft to cap on diff yoke. The angle between the shaft and either yoke shouldn't be more than 5 degrees (3 is better) and the trans cap and diff cap should be within 5 degrees of each other. The weight of the vehicle has to be on the suspension when you do the measurements.

Also you must realize that the differential will try to move upward on acceleration changing the rear angle. If the vibration is only on acceleration, you may want to shim the rear end to point the diff slightly down. If it vibrates on both acceleration and deceleration, something is lose allowing the rear to move around.

 

did not change the angle. just removed lower plates for traction bars

 

but it did vibrate some before. ok measured rear. 9deg. driveshaft is at 0 deg. front yoke is 5 deg.

 

Rear yoke is pointing up or down? Trans I’m sure is down ward?

 

Having 4 degrees difference between the trans and rear seems like too much. Zero degrees difference would be best.

 

up on the rear. the mounts on rear diff housing are buggered up pretty good. rigged. think i’ll remove and install new mounts and do it right. get her zeroed in with new springs since she’s sagging on l side

 

last time I had a problem like this I raised the trans mount up trying to fix the angle before I realized I had a worn ujoint .replaced it smooth as new

 

How much spring wrap is happening when you are into it? Could be adding too much extra pinion angle.
Maybe that's why the traction bars were on there...???