Transmission Stuck In Gear Problems of Mitsubishi Raider

Powertrain: automatic transmission while driving on a speed of about 65-75 mph on the freeway/interstate and all of a sudden I have to slow down by stepping on the brake and then releasing the brake to continue moving again after the speed goes down to about 35-45 mph, the "check engine" light comes on and you can hear the engine revving like it is stuck on third gear instead of shifting to fourth gear. I have been to an authorized napa auto repair shop and the code they found out was a sensor problem. They changed the sensor and sure enough gone again but the "check" engine light came on again while I was climbing up on a slope that is stepping on the gas a little bit more to be able to climb the slope. Went back to the same napa auto repair shop and this time it is still the same problem. They asked me to drive it some more just in case the check engine light disappears again and it did. Now I am scared of driving it anymore unless I have to for fear of anything worse happens. I bought this truck in 2008 with about 35k on the odometer and bought it with "as is" conditions. I could not afford a newer and better truck so I am stuck with this one. I have now 48k miles on the odometer since July, 2008. The napa auto repair shop said that the next thing they could try is getting a used transmission or even a new transmission but would not be able to guarantee if it won't happen again.

See all problems of the 2006 Mitsubishi Raider 🔎.