I have a 91 F150 4.9 w/E4OD - The transmission will not shift from 1st to 2nd until 2500 RPM is reached and then I relax the accelerator. After the transmission shifts to second, everything works fine. If I am traveling over 25 MPH and stomp on the gas to shift back to first and release – the transmission will shift back to second just fine. OD, third, reverse – every thing works with no problem, it is only from first to second, any ideas?

 

Since all other shifts are ok then I will assume the line pressure, valve body, fluid level, and intermedeiate clutch are ok. Your linkage could be worn out. Solenoid might be bad. 1-2 shift valve might be nicked or stuck. Check the D2 valve also.