Hyundai Repair: Loss of power in 98 accent, overdrive switch, hyundai accent

Question
I have a 1998 Hyundai Accent LS, Recently I had a mechanic overall the engine, since then I have been having a problem with the overdrive switch, getting enough power go over hills ( and sometimes to even move the car) and the econ-normal switch does not work anymore. I was told that the problem was with my transmission filter being blocked, I have since replaced it and still have the same problem. Where else could the problem reside?

Answer
The transmission filter won't cause a problem with the overdrive switch or the econ/normal switch.  Actually, I'm impressed that you can tell the econ/normal switch isn't working.  Most people don't recognize any change.

I would start by checking the wiring in the shifter to make sure it hasn't been cut.  A good diagnosis can be done by someone who has access to a scan tool which will read your transmission data.  The status of the econ/normal switch and the overdrive switch are both viewable in the transmission data stream.  

I'm not at somewhere where I can access the schematic right now, and I don't recall exactly how the econ/normal switch works, but the overdrive switch simply selects where it sends power.  In one position it sends power to your instrument cluster (turning on the OD OFF lamp), and in the other it sends power to the transmission computer, enabling overdrive.