88 f150 c6 no reverse!! Help!!
 

Ok had the trans sitting on the floor for 10 years or so went through it new seals and sealing rings clutches all good this came out of a everyday driver and I know it all worked when last in and now no reverse!! I air checked everything before put in everything work and held!! Also new vac mod valve good vac to it brand new clean fluid new converter what am I missing?!! All valves in valve body seemed free but didn't go through that is that a possible prob?!! Any help would be good!! Thanks