by ptommo59 on Tue, 23 Jan 2024 11:54 +0000
When you scanned did you check for pending codes as well as active? As a pending code can cause a lock out of overdrive and clear when you turn off if triggering issue was intermittent.
Here is the items listed in the A750F gearbox failsafe and problem tables in the workshop manual if it helps:
* DTC P0710, P0712 and P0713 (No. 1 ATF Temperature Sensor): During a No. 1 ATF temperature sensor malfunction, up-shift to the 5th gear and flex lock-up clutch control are prohibited.
* DTC P0748, P0776 and P0778)Shift Solenoid Valve SL1 and SL2): During a solenoid valve SL1 or SL2 malfunction, up-shift to the 5th gear is prohibited
No up-shift (4th -> 5th)
* Engine coolant temperature sensor circuit (wont use overdrive or lockup until engine water temp is above 60 degees? ECM uses the CANbus to pass the temp lockout/control info to TCM)
* Speed sensor NT circuit (input shaft sensor and/or cabling on side of gearbox can get knocked and cause intermittent readings)
* Shift solenoid valve SL1 circuit (potentially sticking and slow to operate)
* Shift solenoid valve SL2 circuit (potentially sticking and slow to operate)
* Shift solenoid valve SR circuit (potentially sticking and slow to operate)
* TCM (faulty/intermittent circuit function)