Quote:

I have a Dynotech 4" CM .083 1350 u joints.

It was in neutral when it was vibrating. I rev'd the engine and no cchange. It also only vibrated on coast.

Only thing that has changed was a rear brake bracket was cut off and a new one welded on.




Before the Dynotech driveshaft you twisted one didnt you on the launch on ice.

Your car might be a good canidate to do some test Pinion Angle test measurements.

Can you give all the related driveline measurements, for all and both "pinion angle camps" to decipher.

IMO, No doubt you have some angularity problems.

The Evidence, You blew/broke your first shaft and now your having vibration problems with this shaft.

Also, look further then my pinion angle suggestion.