Just swapped in another 2.8. My ride is an automatic and donor motor is from a manual. Engine ran real smooth before pulled. Now I got a real bad vibration that is kicking my ***. Pulled the motor and ran it on the stand and vibration is gone. Only vibrates while installed. Any ideas?

 

I assume you've inspected your motor mounts and other obvious stuff... Try running it in the car w/ the tranny disconnected? Flywheel? Etc?

 

What year 2.8 did you have and what year is the new one? I did this swap too and I needed Nother flywheel because my factory was a weighted flywheel because it was externally. Alanced and my new engine was internally balanced, check it out

 

Yeah some years have weighted flywheels or nuetral flywheels.

 

Having the same problem, but i went from auto matic to standard. U get a fix? Been told its either a fly wheel or drive shaft.