i tried to reply to you on the pirate board, but it keep locking up on me.
Look at the FAQ on the top of the toy truck forum. Search the page for "motor mount tech".. Chain them down while they are out.
(pic is from the FAQ on pirate)
I kept busting driver side mounts until i did the chain. Now i wish i did the passenger side too. (popped one in reverse.)
To change'em, yea, just jack up the motor by the pan (with block of wood) or transmission.