vibration irratation

[85-m1028]

Well I finaly got my trans put together and bolted up. The engine runs smooth "what a difference with the timing gears" I have noticed when I drop it into drive there is some serious vibrating happening, but stops when I let off the brakes. Is this normal? I do have a new low stall hd converter, and all urethane mounts.

[john8662]

I'd suspect the urethane mounts, they don't obsorb the vibration as well as the rubber mounts did.

What mounts have been changed? The engine mounts or just the tranny mount?

[85-m1028]

motor, tranny, and body mounts are all urethane, doesnt rattle much when idling in park??