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I have a 95 F150 with a 5.8. I bought the truck a few months ago and it had a harsh up shift and into reverse. Down shifts were fine. I took it too a tranny shop for a leak and had them try and diagnose and they didn’t find anything wrong with it but they suggested fixing the code it was throwing. I ended up replacing the EGR feedback sensor and it cleared the code and softend the shifts slightly, but the harsh shift was still there. I had a misfire so I then replaced the plugs and wires and that made, the harsh shifts intermittent. Engine is running smooth now, but it does have a hard start. I usually crank it for a second, stop, and crank again and it fires right up. I have also replaced the RABS and the TPS, but those didn’t really do anything. Any help on what to check next would be appreciated
The next step would be to install a pressure gauge in the test port. The port is on the driver's side of the trans, towards the front, just above the pan. It has a black hex head plug in it from the factory. The thread is 1/8" NPT dryseal. Get a 0-350 PSI gauge. Check the pressure at idle in PRND21. Check it at stall (stall is holding the brake HARD with your left foot and planting the go pedal on the floor with your right foot.) in R, D, 2, and 1 NOTE: DO NOT HOLD STALL FOR MORE THAN 5 (FIVE) SECONDS AT A TIME. IDLE OR FAST IDLE IN PARK OR NEUTRAL FOR AT LEAST 30 SECONDS AFTER EACH STALL TEST.