TKO600&Moser12bolt do I need to shim to get proper pinion angle for 69 bird?

[RBR]

I have been driving the bird and i'm trying to work out all the kinks now. I feel a vibration at about 60mph. It goes away at higher speeds and lowwer speeds. Is it common to have to shim the rear end to get proper pinion angle? I have a tremec 5speed and moser 12bolt.
My very crude measuring shows the tranny a little lowwer in the rear and my driveline and the rearend seem equal.
I'm droppinp my drive saft now and attemping to get a better measurement.
Thanks for any replies.

[RBR]

Here are the best measurements I could get with a smart level and a dail type level.
Rearend \ .7 degrees pinion pointing downward
drive shaft\.4 degrees front of driveshaft pointing downward
tranny /3 degrees rear of tranny pointing downward

So front of rearend is pointing down, front of drive shaft is pointing down, and the rear of the tranny is pointing down.

I think I need to raise the front of the rear end to match the angle of the tranny and try and create parallel lines. So the rear would be 3 degrees raised in the front/pinion.

I'm I going in the right direction?

[The WidowMaker]

right now your working angles are 3.4 in the front and .3 in the rear and are causing your vibration. they need to be within .5 of each other. usually, the pinion is .5 greater to allow for wrap up.

you could shim the tranny for the best results, but i would just raise the pinion a couple of degrees to get them to match for now. drive it and see if it still vibrates. if it does then the tranny will need to be raised.

if you found the distance from the motor mount to the tail shaft, the length of the driveshaft, and the distance from the axle centerline to the pinion yoke, you could do some trig to figure out the numbers to an exact amount.

[RBR]

Hey thank's for the reply. Plan to make the changes soon. I'll keep you post on how it turns out. I just fuond out that my rack&pinion is bad so I have that on my plate as well.

[RBR]

I raised the rear end and it seemed to help. Now I'm thinking that the motor I'm running is prone to vibrate at higher RPM's. I have an 85 and older style GM crate motor from mexico. I've been told that it is the nature of the best for this type of motor. I'm still in the learning curve! Fixed the rack and pinion, was able to just put a new tie rod end on it.