No go

Any one have any advice on where to start looking on my tractors hydraulic circuit. It's a case 224, 1987. Had to pull the motor out for a re-re-rebuild and just got it back in. Got evrything put back together and leveled the deck. Started the motor up and moved the travel control lever in reverse and nothing. Tried forward and the same thing. Then tried the deck lift and that worked fine. Checked the linkage to the travel control valve and everything appears correct and working. The tractor was traveling fine prior to pulling the motor and having it sit for about two weeks. Nothing was touched with the linkage or hydraulic system while the motor was R&R'ed.
Any advice would be appreciated.

Thanks,
Tim