Transmission's in

Well I got in and all hooked up yesterday. Got my external filter all plumbed up and mounted today. Decided to try and run it a little while still on the jack stands to try and find any problems before actually road-testing it. Looks like it's a good thing I did........ First it seemed like things were OK, then heard a clunk so shut everything down to make sure nothing broke that I could tell from the outside. Everything looks good.... OK then, so started it back up and darned if reverse don't work now and the wheels turn like it's in drive when it's in neutral......... According to the book, both symptoms have the same common problem....... The forward clutch not disengaging. After going over my ATSG book and my FSM (that just happened to come in the mail today while i'm out working on it) I'm thinking (hoping) it's just a stuck valve in the aux. valve body keeping the forward clutch engaged. The valve I think the problem may be moves one way in LO and the other way in Reverse......... So tomorrow i'm dropping the pan and the aux. valve body to see if that valve is stuck............ So hopefully road-test tomorrow...........