No O/D, harsh 1-2 shift 93 Probe SE AT

Hello, Please help me out here if you can to fix daughter's Probe SE with 2.0L. 1-2-3 shifts are normal when accelerating slowly up to ~25 MPH when O/D light starts flashing. After that, no O/D and very hard 1-2 shift followed by not-quite-so-hard 2-3 shift. Shifts 1-2-3 fine after every startup until the dreaded ~25 MPH mark. Initially had trouble code 06 (Vehicle Speed Sensor) and 55 (Pulse Shift Generator). After clearing codes, only 55 remained. So, I changed the PSG--same problem and still have code 55. Transmission has same no O/D and hard shift problem whether the PSG is connected or not; could wiring harness or PCM/TCM be the culprit?. If I disconnect the VSS, I have no speedometer and transmission doesn't shift out of first gear. I assume that means the VSS is working, or is it possible that the VSS works OK for speedometer to work but doesn't output sufficient or correct signal for transmission to work properly? I'm at wits end. :banghead: Appreciate any advice. Thanks.

Ron

i may be that the transmission fluid is low or burned and thin causing problems with the movment in the clutch plate or it could be that the whole transmission is starting to fail as this has been a substantial problem with most probes.
(the above pertains to automatic trans)

if by chance it is a manuel it is definately the clutch and needs replacing.

Check your TPS (throttle postion sensor) attatched to the throttle body. I had the same issue once after working on my car and it turned out that I forget to attatch the TPS connection back up. I have an ATX, but it did tthe exact same thing until I reconnected it. Mine would rev real high in the low gears and then slam into second. It sounds to me like this could be your porblem.

Thrax23, I don't think the transmission itself is the problem since I get good shifts until car exceeds 25 mph. Then the overdrive ligh flashes and hard shifting occurs.

Jeepme1, I think I'll disconnect TPS and see if I get the same result you did when you forgot to connect the TPS; at least that's an easy test. Except if I have a bad TPS, I should show no improvement. I know the TPS is connected since I've disconnected and reconnected every sensor associated with the transmission hoping I just have a poor connection.

Thanks to both of you for your comments.