'93 Mustang LX with a 4 cyl engine and the A4LD transmission. Transmission will not shift from 3rd to 4th. Shifts fine to all the other gears. I dropped the trans pan, changed the filter and put in new fluid. The trans fluid was clean and no debris present. I checked the 2 solenoids in the trans and they were functioning when I put 12v to them and grounded them. I ran a computer check on the EEC-IV system (with engine not running) and got the following codes: 629566. The 62 code says "Transmission Clutch Fault". Where do I go from here???