Code Help P0734

[CDenton]

2010 Dodge 3500 4-wheel drive, 99k miles. Truck just started pulling this code (P0734). I have a steep incline on my road out that has a stop sign at the top. When I get to the top and check for traffic to go left or right it does a bit of a “rev” like it doesn’t want to stop. I make my turn and the engine light goes on. Yesterday it stuck in fourth gear, got it out by turning off. When I put the tow/haul on it doesn’t turn the engine light on. Any help or suggestions are appreciated. Thanks

 

[transe]

P0734 is a Gear Ratio Error in 4th fault, which means the trans was slipping internally in 4th gear. That is usually caused by a weak OD clutch.

But it's unusual that you're apparently setting the fault at low torque (closed throttle). Usually a weak clutch will slip at high torque, not during coastdowns. I would have a dealer read (and print out for you) the DTC Event Data for the P0734 fault. This is a block of data that gets written into memory in the PCM whenever a trans fault is set. You can have up to 6 banks of DTC Event Data (so if the fault set more than once, there may be multiple sets of data). The DTC Event Data shows what was happening (engine speed, turbine speed, output speed, throttle angle, gear position, line pressure, solenoid and pressure switch states, etc.) at the moment the fault set, so it can be useful in diagnosing the problem. For example, if it shows engine speed = 1300 RPM, output speed = 1420 RPM, and turbine speed = 0 RPM, then that would point to a bad input speed sensor (or a wiring problem with that sensor) rather than an internal trans issue.