Norv, I don't think it makes any difference if the car is level or not. All you have to do is take a reading of of the slip yoke bearing face which will give you a reading of the transmission angle and then take a reading on the driveshaft angle and the difference in the two readings is the ujoint operating angle.

You are absolutely right silverstreak. The difference is all the counts.
The 5 degrees that Signguy got was not a true reading but if it was 5 degrees would be too much. An honest reading of over 3 is marginal.


Guys this is important for smooth running and the only way to do the job right is to raise the transmission the maximum you can then make the pinion match but in the opposite direction. Try for less then 3 degrees.

 

Then lowered the rearend 1 inch in the back and about .5 inch at the pinion to balance both operating angles at 3 degees to achieve smooth operation

From this I assume you dropped the rearend crossmember. How did you do this. The crossmember sits in rubber cups, if you spaced it down how???

People normally try to raise the crossmember in the frame not drop it down.

 

Gene if your exhuast is rubbing the ground why not just tighten up on the hanger bolts to raise the car. if the spring is shot get a new one. If your Bal?s are touching the ground get a higher seat. :lol: :lol:

 

Mr vette, I lowered the front of the pinion by using a longer bolt and used large washers the size of the rubber mount, so the mount would be supported evenly. Then at the back I made plates the size of the rearend mounting pad where it bolts to the cross member with the four bolts. Like you said it raised the car so I put in longer spring bolts and put the car back to its normal ride height, other wise you would have to realieghn the car. It let me get both operating angles to 3 degrees and the drive line is back smooth all the way to scary. One thing I am not sure about is what lowering the third member in the car has done to the roll center, I feel like it improved it but that is only a guess. SSS

 

Norv I dropped the rear of the pumkin more than I dropped the front which did two things, it decreased the operating angle of the front u-joint about a degree and a half and it also aimed the pumkin up to make it parrall with the transmission. Unless my car is different than most c2-3s I think that most people using Tremecs (unless they cut the tunnel or lower the rearend) are running about 5 degrees u-joint angles and are going to have long term problems. Just my 2 cents worth. SSS

 

Mr vette, I lowered the front of the pinion by using a longer bolt and used large washers the size of the rubber mount, so the mount would be supported evenly.

In all cases the front of our pinion needs to be raised, in all cases. If you had to lower yours it is because the rear was lowered toooo much. Dropping the front to compensate for over lowering the back is not a good idea. Remove some of the shims from the back.

When I installed my Tremec I placed a jack under the rear of the transmission then pushed it up tight against the floor, I marked the places where it hit and it was in the hole for the shifter and shifter tower to pass through, I would lower the transmission then cut the offending area. I did this until the tower for the shifter easily passed through the floor. I then make a frame like a picture frame and fiberglassed it around the outside of the new enlarged hole, I did this from the inside. I then drilled a series of holes and tapped them for 10/32 , made a heavy rubber sheet with a hole punched in it to pass tightly over the shifter and bolted it down to this aluminum frame. This sealed the hole to make it water proof just in case and keep fumes out.
I also reworded the area around the output yoke.
I ended up with -.75 down taken off the yoke of the transmission.
A little reducing of shims in the pinion again taken off a cleaned up yoke gave me + .75 up.
Alignment left and right are another story.

In summery I guess shimming the rearend down with shims between the housing and crossmember is the best way to lower the rearend, I was aftaid it was done somehow with the cups that the crossmember sits in and that is a bad way.
Long hanger bolts can cause problems with rims, too long and they can rub.

 

One other tool I made was a plate the same size as the yoke. In the exact center of this rectangle I reamed a .499 hole. This plate when held aginst the face of the yoke without the other half or U clamps installed fits really well. I then took a 1/2 inch ground rod about 27 inches long, sharpened both ends on the lathe then press one end into the underside hole. I keep pressing and adjusting until the plate when held on the yoke centered in the drilled center hole that all yokes have but at the same time would lay against the front of the yoke.
I used this as an accurate pointer to either point from the pinion to the transmission or transmission to pinion.
It allowed a good left to right adjustment.