I hope this is a good place to post this question.

I have a Snapper SR1028 lawn mower (rider) that won't move. It
starts great etc. Last week when I was mowing it stopped completely
and the rubber part of the clutch tore off. I replaced it with a new
one. It cycles properly in R-N-1-2-3-4-5 and moves the clutch along
different parts of the wheel like it should ( i don't know the
technical terms). The belts are good etc. The wheels turn, but they
don't turn the same direction at the same time. For example when you
turn the right wheel forward, the left wheel only turns backward and
visa versa. There are two (what look like gear boxes) attached to the
rear axle. One large one close to the right wheel and a smaller one
that looks like it attaches to the disc (or clutch, whatever you call
it) and subsequently to the left wheel. It won't budge in neutral,
because the wheel won't move in the same direction..

Any ideas on what it could be? Also, when I flip it on it's back
(vertical position), how long do I have to wait to start the engine. I
don't want to damage it because the oil is in the wrong place! P.S. it
is meant to flip on it's back.

Thanks!!