Turbo Action full manual valve body issue.

After installing the valve body the car will not move in reverse with out hitting the throttle. Also it slips in first leaving from a stop sign (like a neutral drop). It revs to about 1500 and smashes into gear chirping the tires

Called turbo action and they said since I bought it used there could be a check ball missing in the reverse circuit?

Anything else I can check while its still in the car?

Plan on putting the old VB back in this weekend to make sure its not the trans.