Just replaced the shift pack solenoid in my truck since the continuity on the trannys harness came out to be fine. Before I replaced the SPS I had a code (P1746 Pressure control solenoid circuit open). Right after I replaced the SPS the trans was doing great untill the day after all my problems came back shifting very hard and OD light flashing. Also when the trans gets into 4th it makes a really weird hissing sound as dumb as it sounds I've never heard it do that. Ive thought the trans might be building to much pressure or not enough. At this point I'm really not sure what to do with it maybe a PCM reset?