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
Geo Prizm Automatic Transmission May Not Shift Correctly at High Mileages
Geo Prizm Problem
Average Mileage: 159,925 mi (125,000 mi - 225,200 mi)
Visitor, 1994 Geo Prizm, 132,787 mi
On a cold start, the car won't shift into high gears until it has warmed up. My driving is all highway and I'll be cruising at 65 mph in 3rd gear. I can barely hear myself think until it suddenly decides that it should sift.
I haven't had it fixed as I've already ordered a new car and don't want to be putting money into this.
Visitor, 1994 Geo Prizm, 125,000 mi
Doesn't want to shift when cold. Used to be just over drive, now it's all gears.
Stays in 1st gear for half a block. Takes 2-3 miles to shift into overdrive.
Visitor, 1991 Geo Prizm, 160,000 mi
same problem, will not shift until it warms up to operating temperature
Visitor, 1997 Geo Prizm, 153,000 mi
shifted like a stick shift from 1st to 2nd.
Visitor, 1997 Geo Prizm, 225,200 mi
transmission is an automatic. on the highway, it runs along at 60 MPH in 3rd gear at 3000 rpm, and when I start up a hill, it shifts into fourth, as soon as I head back down the hill, it drops back into third. As this problems persists, my mileage has dropped about 15%, from 38 on the highway down to about 31.
My car can't even pick up the second shift!:-/
Visitor, 1996 Geo Prizm, 130,000 mi
Major forward gears slipping. Reverse ok.
Visitor, 1997 Geo Prizm, 197,000 mi
When cold and sometimes not the car will not sift correctly.
Visitor, 1996 Geo Prizm, 173,266 mi
unless at operating temp the trans does not shift into overdrive, throwing dtc, shift solenoid E