Can anyone tell me how to fix a Shift solenoid CKT stuck on code 757 B and code 760 performance GR stuck in off positio? Tks.

 

These are 2 different problems; the first, if taken (I hope they are supposed to be P0757 and p0760) is a hydraulic concern, the second is circut related.
Let's start with the second first: this means the PCM didn't see the return voltage back on the pin that goes to the specific shift solenoid (If memory serves correctly, its shift sol. c or #3). You could start by checking fuses,obvious wiring concerns, etc.
However, it really doesn't matter as the first code is deadly. It means that when the trans was commanded to shift into a particular gear, it didn't get the ratio it wanted. You might have experienced a slipping, rough, or missing shift. This is indicative that the transmission has something wrong that means it couldn't obtain the gear it wanted when commanded; usually, it means the trans is damaged.
As these are Asian transmissions, they are 5 or 6 speed trannies, and most of these problems become obvious during a rebuild.

 

Thanks alot I will check this info. out!