The issue with automatic RAV4s is not a faulty gearbox but the ECM/ECU which goes bonkers after about 60,000 miles thereby sending wrong signals to the transmission.
Signs to look for are:
Check engine light always on
Diagnosis points to shift solenoids
Loss of power
High revving
Gear engages with loud clunk
If you notice these signs please park the car and get a new ECM. Replacing the gear box at this stage will not help as the ECM will damage it again.
Yes I should know as I have been a victim early this year at a cost of about 235K
(gear box at 130K and ECM at 105 K).
PS:Do not buy an ECM at 60K as these are refurbished.