Chrysler Repair: Code P0731, plymouth voyager, volume indexes

Question
98 Plymouth Voyager 3.3 Flywheel was cracked so pulled trans and replaced also I put in new input and output sensors when reinstalling Filled to correct level of Correct chrysler Fluid.  But stays in lower gear will not upshift. any help would be appreciated.

Answer
possible causes

UD AND L-R PRESSURES < 95 PSI AT 2000 RPM
DELAYED 1ST OR REV ENGAGE/COAST DOWN STOP BUMP
UD AND L-R CLUTCH VOLUME INDEXES OUT OF SPEC
UD PRESSURE < 5 PSI IN 4TH GEAR
TRANSAXLE REPAIR (L-R SEALS)
L-R ACCUM SEALS WELDED TOGETHER
L-R SWITCH VALVE STUCK IN REV
UD ACCUMULATOR SEALS
TRANSAXLE DEFECT(UD SEALS)
TRANSAXLE SEALS ARE DEFECTIVE
UD PRESSURE > 5 PSI IN 4TH GEAR
L-R SWITCH VALVE STUCK IN FIRST GEAR POSITION