Transmission Problem

I have 2002 Hyundai Accent 1.6L automatic. I have recently had a new transmission put into the car. Since then I have had a problem that no one can figure out.

After maybe 20mins of driving my car will get “stuck” in 3rd gear. If I’m on the highway, the car won’t go into 4th. Or if I start from a light the car will start very slowly and I have to put the gear shifter into 2nd gear. If I stop and restart the car the problem goes away for another 20mins or so. Time varies for day to day.

I have 2 codes that show:

P1529 : Manf cntrl veh speed
P0734 : Gear 4 Ratio Incorrect

I just took the car back to the trans shop and they did a whole trans service, which didn’t seem to help much.

Thanks for any help! P1529 means that the TCM (Transmission Control Module) is commanding the ECM (Engine Control Module) to initialize the “MIL”. In other words the TCM wants the ECM to turn on the check engine light. This is because the TCM has received information saying that there is a malfunction within the transmission. A common malfunction is a failing input or output sensor. The fact that PO734 is set could also be the reason for the setting of P1529. PO734 is set because the transmission won’t shift into fourth gear. This could be due to either an electrical issue, electronic issue, or mechanical issue. Possibilities for the setting of PO734 include a transmission hydraulic control circuit issue, dirty transmission fluid, low transmission fluid level, wrong type of transmission fluid, an issue with shift solenoids, or transmission mechanical issues. If the actual fourth gear position is higher than the fourth gear position proposed by the TCM, the slip ratio will be greater than normal. When the ratio exceeds its specified value, the TCM sees this as a malfunction. The diagnosis is to monitor the actual gear position by checking the torque converter slip ratio against the formula below. The goal here is to determine the slip ratio of the torque converter.

(1) What are the output shaft revolutions from the revolution sensor?

(2) What is the engine speed signal from the ecm?

(3) What gear ratio was determined, in relation to the gear position that was proposed by the TCM.

1x3/2 equals Torque converter slip ratio

Simply stated the rebuilding job was most likely done incorrectly. Go back to the shop that did the rebuilding and have them correct it.Car Repair Talk's forum.