Thump noise when shifting

I have just recently started driving my celica, and idk if this is normal, but when i shift gears sometimes i hear a thump noise in the back. There's also a thump noise when i drive forward, stop, and then it thumps when i reverse. Just one thump each time, it's not a constant noise. But it is definaly coming from the back of the car. What could this be and how would i fix this?

It's most likely your rear diff mount.

This thread has good info on what options you have to fix it.
http://www.alltrac.net/phpBB2/viewt...ostdays=0&postorder=asc&highlight=mario+mount


Here's a write-up on how to do it
http://www.alltrac.net/phpBB2/viewt...postdays=0&postorder=asc&highlight=diff+mount

I used poly, & it's held beautifully for 3 years now.
$40 bucks for 3 mounts, good deal in my book.

http://www.alltrac.net/phpBB2/viewtopic.php?t=3703