When towing with my 04 F-150 HD and begin climbing a hill, transmission downshifts from OD (as it should) but the RPMs aren't as high as if I lock out OD. What is happening here. I have the XL so I don't have tachometer so I working by sound here. Thanks for any information / Skip

 

It is only a 4 speed tranny so locking out the OD only keeps it from going into 4th. Try giving it more gas or maybe down shift again and give yourself that little extra bit of torque.

 

Thanks for the information but I apparently didn't state my case very clearly. I've got plenty of power. My question was "when the transmission downshifts from OD it SEEMS to be still running at lower RPM than when running in 3rd gear". With it being a 4 speed transmission how can this be. After it downshifts if I then lock out OD the RPMs raise even more. It's like there is a gear BETWEEN 3rd and OD??? I don't think it is anything to do with the lock up mode because even when I reacy the top of the hill and let up on the gas (still in 3rd gear) it doesn't drop back to the same level as when it downshifted from OD. I don't mind it's just that it would be nice if I could actually TOW at those RPM instead of either OD or 3rd.

 

Your truck is going along in OD/4th. If needed, your truck unlocks the torque convertor STILL in 4th and rpms raise. If more is needed, it downshifts into 3rd. What you've described sounds like perfectly normal operation of the transmission and the lock-up torque convertor. The unlocked torque convertor feels like a gear between 4th and 3rd. FYI, the torque convertor also locks in lower gears.