DodgeForum.com - P0734 Only in overdrive

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P0734 Only in overdrive

2002 Dakota Sport 4.7 45rfe 270k miles
Only in OD it Started acting like it was going into neutral when above 45/50 mph and if going up hills the Rpm would bounce up and down a few hundred. If it acts like it’s in neutral it will jerk hard back into gear. And if it does it so many times it goes limp and throws a p0734. But if I clear it and turn OD off it switches all gears smooth. Ive changed fluid and filters and it was reddish colored like normal but had an odd smell to it. Changing fluids did not alter anything and it still does it. Valve body and accumulator plate doesn’t seem to have any damage. And no shreds of metal. There was a fine metal powder on the magnet but I figured this was normal? Something electrical? Something mechanical? If any more info needed let me know please and thanks.

OD-Off should only disable fourth and Fifth gear. I don't have an FSM handy that includes the 5th gear TCM flash programming. I think it also forces second prime instead of regular second, but not positive on that.

Quote:

Originally Posted by FSM Page 21-514

OPERATION
At key-on, overdrive operation is allowed. Pressing

the switch once causes the overdrive OFF mode to be entered and the overdrive OFF switch lamp to be illuminated. Pressing the switch a second time causes normal overdrive operation to be restored and the overdrive lamp to be turned off. The overdrive OFF mode defaults to ON after the ignition switch is cycled OFF and ON. The normal position for the con- trol switch is the ON position. The switch must be in this position to energize the solenoid and allow a 3-4 upshift. The control switch indicator light illuminates only when the overdrive switch is turned to the OFF position, or when illuminated by the transmission control module.

https://lh3.googleusercontent.com/Go...4=w675-h872-no

https://lh3.googleusercontent.com/_o...C=w386-h650-no

https://lh3.googleusercontent.com/z6...F=w672-h872-no

https://lh3.googleusercontent.com/hx...x=w678-h872-no

So should I start looking at a rebuild or remanufactured transmission?

Have you done any work to the trans previously? Changed gears, or tire size? That code is whining about incorrect gear ratio........ which is just odd. :) Slipping clutches???

No, the only things I’ve done to this truck are alternator, control arms, and a dual exhaust. As well as routine maintenance. Everything else is stock. Like I said though in drive It goes 1-2 2-3 3-what feels like neutral. Then jerks hard to 3rd again I assume. Then all the way back to 2nd in limp mode after 3 or so attempts. But if overdrive is turned off with the button I have no jerking or anything.

Then either the O/D solenoid is bad, sticks, or something else is jammed up somewhere. If it just freewheels in what should be O/D, that would explain the code...... No clue how to diagnose that one.....

Since Third and Limp are functional, that rules out the overdrive solenoid in a sense (or so I'd think). I'd be looking more at the 4C solenoid. I don't know if there is a way to force second prime to test the 4C clutch.

I’ll try to take a video of what it does when I get off of work this evening.

I also forgot to mention, when I changed filters and replaced fluids, I got a p0871 if I recall correctly. But I cleared it and added more fluid since it was a little low and It hasn’t come back.

here’s a video of what it does. Kind of a bad video but it works.