meh, i wouldnt say its necessary. sliding the tranny down on a pry bar will help a ton since it wont get snagged up on anything. just be careful of the transfer case, it likes to pin itself while your moving the motor around. make sure it stays free and doesnt get pinned by the motor.
be sure to have like 4 jacks when u do it lol, u will be disconnecting 3 of the 4 motor mounts