1999 Dodge Ram 2500 4WD, Transmassion will not up shift.

Nathaniel, Check transmission fluid level and top up if required.
It does sound like a problem with shift solenoids, and should be checked and diagnosed by a good transmission tech.

Bernard's Blog: Dodge Transmission Output Speed Sensor

bernardsblog.blogspot.com/.../dodge-transmission-output-speed-sensor.h...
Sep 8, 2009 - The code was straight forward - PO720 - Output Speed Sensor Circuit.... words but if you've never seen the underside of a 1999 Dodge Ram 1500 pickup ...My 99 Dodge 2500 Ram won't accelerate..transmission is NOT ... RR - If the engine revs but the vehicle doesn't speed up then the trans is slipping.

• transmission control selonoid.

it is probly in the valve body in the trans

MOST DODGES (NOT THE MOTOR BUT THE TRANS HAS A SHIFT SOLINOID IN THE TRANS
THIS PART IS ABOVE THE VALVE BODY OF THE TRANS SO IT IS NOT EASY TO REMOVE
BUT YOU CAN DO IT WITH OUT DROP[ING THE TRANSMISSION YOU WILL IN MOST CASES HAVE TO REPLACE THE VALVE BODY GASKET
THE SOLINOID IS ABOVE THE VALVE BODY ...
YOU WILL BE ABLE TO SEE IT ONCE YOU REMOVE THE VALVE BODY REPLACE THE SOLINOID SHOULD HELP WITH YOU SHIFTING PROBLEM

With truck running check transmission fluid level add if low

Is the 1-2 shift at the right speed or is it high? Does Reverse work? Does it just not shift into 3rd or does it slip?

Code 1762 is the governor pressure code which indicates an internal transmission problem with presssure to the governor which initiates the upshift. This may have been a previous problem and remaining in history or there still may be a problem. I would clear the code and drive it some more. If the code comes back, you will need a transmission specialty shop to diagnose the internal transmission problem.

I have a 1999 Ram B 1500 Van, auto transmission, 5.9 L engine.
Same problem, trans hesitates in 2-3 upshift, sometimes 1-2
to 2-3 upshift. Posts trouble code P1756 - Transmission Govenor pressure too low at below 15 to 20 Psi. Transmission pump shot or valve body leak stops trans from reaching proper pressure to shift, which is minimum 15 Psi.
Either trans is leaking in valve body, valve is stuck, shift solenoid on valve body is sticking, or pump is shot.

Sounds like the speed sensor on the rear axle.