Gearbox stuck in 4th

[Silverfox1111]

G'day all
Has anyone had their gearbox stick in 4th gear?
We were travelling on a freeway at between 100 & 100kmh when I realised it wasn't changing out of 4th gear. Tried planting the right foot, lifting off the accelerator & using manual mode but it still wouldn't change. Only after I pulled over then got going again would it change properly. Did it twice on the weekend, roughly 2 hours into the trip on both separate days. The car wasn't loaded up & no codes came up when I scanned it.
Silverfox

[Rob_Wood]

Under warranty? Toyota
Out of warranty? Automatic Transmission Service Centre of your choice.
Either way, get a general service done, during which they should check everything is operating to spec.
In the old days they'd check band tensions etc. I'm told the system is different nowadays, but a specialist should be able to help you out.

[Silverfox1111]

Still in warranty but I cringe every time I used to take it to them numptys.
It's only ever done this twice & coincidentally they were within a section of road that was within 100km of each other but heading in different directions on different days.

[Rob_Wood]

Still in warranty but I cringe every time I used to take it to them numptys.
It's only ever done this twice & coincidentally they were within a section of road that was within 100km of each other but heading in different directions on different days.

From Dapto there'd be a number of Toyota Dealerships within reach, throughout Wollongong, Upton Thirroul and surrounds. Ry going to a different dealership.

[ptommo59]

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)

[Silverfox1111]

Had no pending codes & have just come back from a 800k drive with no dramas.
It goes in for a service next week (not at a dealership) so I'll mention it then.
Silverfox