At higher mileages, (125,000-150,000) the automatic transmission may not shift correctly. This can be caused by the throttle position sensor being out of adjustment or a shift solenoid needing to be replaced. Typically the transmission does not need to be completely overhauled.Google+
Car Problem Reports
Toyota Pickup Automatic Transmission May Not Shift Correctly at High Mileages
Toyota Pickup Problem
Drive Trains Affected: 2WD, 4WD
Average Mileage: 150,005 mi (114,000 mi - 186,011 mi)
Visitor, 1994 Toyota Pickup, 2WD, 114,000 mi
Won't shift unless let off the pedal..