I have an 01 Ranger with the 4.0l. My truck was running fine and shifting smoothly on a trip. On the way back reverse became hesitant to engage and In drive I only had 1st and 2nd gear. I have replaced the transmission speed sensor the vehicle speed sensor the four shift solenoids the tcc solenoid the ecr solenoid and changed the gasket's for the valve body plate. And I still have the same result. I have the mechanics at Ford scratching there heads. Anyone have an idea what it is?

 

Welcome to the forum


Not sure why transmission mechanics would be scratching their heads?

P0734 is a specific shaft speed ratio issue so not a sensor issue or solenoid issue

Trick with OBD codes is to look at what the computer DID NOT USE
List here: OBD-II Trouble Codes

Computer could have set a circuit fault code for sensors or solenoids but it didn't
It set P0734 - shaft speed problem
And P0734 is a specific ratio problem as well so that should tell you it can't be a bad shaft speed sensor because that would set codes for all ratios

So this will be a tear down, not a patch

The slow Reverse is a sign of low pressure, as is missing higher gears, if they test the pressure I am sure they will recommend rebuild

This was just a guess on my part from your description

But go over all the P07XX codes, see what computer can pick from for transmission issues, it can be very specific, so what it doesn't choose is as important as what it does choose

Engine codes are the same, lots to choose from, so whats not used is import there as well

Worse thing you can do is to Google an OBD code and base any decisions on it's definition, first off it is not in english, lol, reads like English but it ain't!!, it is binary machine code loosely translated into human
So look up full code list, then find the code or codes you have to go on from the computer, look at similar codes computer did not pick, really helps