The reverse gear in my F150 has started slipping all of a sudden, with no noise or notice. All forwards gears are functioning properly. If I rev up the motor in reverse it seems like it wants to go, but I get the wrench light/safe mode and it now has a P0720 code. I've done some research and replaced the Output Speed Sensor and replaced the tansmission fuild and filter. I cleared the codes once before I changed the sensor, and now my reader indicated the the P0720 is "Pending". Do I have to keep trying to use reverse? Drive it more? Plus it looked like after driving it today that I might have overfilled the transmission.

Any suggestions with be greatly appreciated!
George

 

Ok..last chance here..changed fluid and filter, Output speed sensor and cleaned contacts on ALL transmission sensors. If the truck is on a little incline, it will engage and go slow, giving it gas doesn't help. Works better is 4WD low. Going to call the transmission shop in the morning. Anyone have any other ideas before I call the shop?

Thanks!

 

Its not going to be the output speed sensor.

It will be a problem with the reverse band, reverse servo or the reverse drum.

Check to see if you have engine braking in manual low. If you do, the problem will be with the reverse drum inside the trans. If you don't, the problem will be with the reverse band or servo. The only hope you have to fix this without removing the transmission will be a problem with the reverse servo. It is accessible under the valve body.