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.
Car Problem Reports
Toyota T100 Automatic Transmission May Not Shift Correctly at High Mileages
Toyota T100 Problem
Drive Train Affected: 2WD
Average Mileage: 137,348 mi (117,000 mi - 149,600 mi)
Doesn't shift from 2nd to 3rd when cold. When engine temp is on the way up to normal, it will shift. A 2 minute warm up usually works. Also shifting onto OD doesn't usually happen until 55 MPH, even when driven for 10 miles or more. Letting off the gas at 50-53 MPH will sometimes allow it to shift but not always.
Visitor, 1997 Toyota T100, 2WD, 149,600 mi
Transmission fails to shift properly at the 2-3 shift when cold. Called toyota and they have informned me it is normal. this process is to get the A/T fluid up to temp