1997 F-150 4.6 V8. I was driving one day going 45-55 and all of a sudden my RPM's went up and lost acceleration. Since then, when overdrive is ON, it stays in 1st gear and doesn't shift out but the RPM's just go up. When overdrive is OFF it drives in 1st gear, and feels like it shifts into 3rd gear around 12-15 MPH and stays in that gear. When I come to a stop it does the same, like I only have 1st and 3rd. It gets to about 40 before RPM's are really high. I heard one of my solenoids could just be burnt out. Also, there is no transmission slippage, it shifts fine with no odd noise.

 

The first thing to do is to get the codes read. The places that read codes free CANNOT read the codes that you need. You'll need to pay a good independent shop or a Ford dealer, or find someone near you with an Auto Engenuity setup.