Off topic..Dodge truck tranny question????

[diesel4me]

Friend has a later model Dodge Dakota truck in his shop...truck is stalling when you shift into reverse.(automatic tranny)...almost like the torque converter is locking up in reverse!!...will idle in "drive" without stalling,but dies right away when put in reverse..if you attempt to give it gas while shifting into reverse,it starts to ping and run erratically too!..idles a bit rough in drive,but does not stall,or run eratticly like it does in reverse..!..it does not always do it--some days it drives fine,then will act up out of the blue!..

He's tried checking the EGR valve,O2 sensor,cleaned the throttle body and idle air control valve,etc..no problems found,no "codes" stored either!..

The tranny has very few electrical plugs,only for neutral safety and back up lights,not a "computer controlled" one as far as we can tell,so somehow the tourque converter must lock up hydraulically or mechanically??..resembles the older Torque-Flight ,but has overdrive..V-6 motor..

We are baffled...anyone else have any ideas??....(other than junking it--we already suggested that to the owner! )...

 

[rjfguitar]

Well, the lockup is an electronically activated hydraulic motion. Something is goofy there, as I'd almost suspect something other than the trans, like a computer issue. The reason I say that is because the torque converter is not controlled electronically, outside of the lock up clutch. A mechanical part should not care if it's in reverse or or forward, and I would also think it's not in the reverse clutches. I The converter spins freely regardless of what gear and doesn't stall until proper RPM's are reached.

I would think it's in the ECM. I wouldn't be a bit suprised if you had another ECM laying around, swapped it in, and it worked fine.

I know that can sound odd, but everything else is essentially mechanical. If the engine runs fine in drive, it should run fine mechanically in reverse. Same goes for the trans, a converter isn't going to stall at idle when you put it in reverse, it's a manual fluid coupling.

It would be an electronic deal that would cause the converter clutch to actually lock when it's put in reverse or, the ECM killing the motor or causing the motor to die when reverse is selected.

Totally sounds electronic to me, but I could be wrong I guess.

 

[dave_90_blazer]

FYI, that is a 42rh trans(basically a 904 w/OD)

the lockup and the OD is computer controlled, nothing else

 

[darryl]

i'll check tomorrow and post the cure but if my poor memory serves me one of the lockup valves in the vb is stuck in the on position no fluid is sent thru the valve until 2nd gear so the 1-2 shift should really make the engine stumble but for some retarded reason fluid is also supplied in reverse causing the engine stall

 

[darryl]

okay checked the flowchart in rev vs drive the switch valve is stuck and in rev you are losing flow to the converter front side dodge calls it front oil and lack of this causes dragging lockup in rev

 

[southernspeed]

Good info at www.dodgetalk.com

 

[diesel4me]

Thanks!...

I'll relay the info learned here to my friend!--he'll most likely send his customer to a tranny shop--he'll replace a tranny,but doesn't "fix" them,other than fluid and filter changes,etc..

We suspect it is that valve in the valve bodysticking..he's going to try unplugging the lock up coverter wires and see if it still stalls in reverse..if so,it's going to the tranny shop or Dodge dealer..

I've seen a ton of Dodge trucks with automatic tranny troubles lately--many failed completely at low mileage with no abuse!..after reading the website linked above,I'm not sure I'd buy a Dodge truck--they seem to have lots of tranny and differentials failing at low milage..they should have stuck with the Tourque-Flite 727's ,IMO...