Have code P0750 ON MY 96 EXPLORER 5.0 V8 WHAT IS THAT AND WHERE IS IT LOCATED???

Thank you for your reply. I will check further into the shift solenoid just has soon as I can. The transmission fluid has been changed out and the filter has well. any other advise you can give me to help with increasing fuel mileage would be gratefully appreciated. I have changed the spark plugs and wires and air filter. I was told that it could be a problem with the MAF sensor has well. Can you tell me what that is and where it would be located on my 96 explorer xlt 5.0 v8 engine. I have the AWD explorer. I am getting any where from 9-12 mpg rite now. What would you suggest me to look for??? Again thanks for pointing me in the rite direction.