Sick and tired of throwing money at this 04 Dakota 4x4 4.7l, does anyone have an actual Fix for No first gear p0731, no O/D. Have replaced the Solenoid pack that I keep hearing about, Fluid was clean, full, looked new, nothing in the pan, replaced input and output sensor, No change, An actual fix not an educated guess would be nice. Thanks.

 

• Diagnostic trouble code (DTC) P0731 stands for “Gear 1 Incorrect Ratio.” This code implies that the transmission is slipping. The powertrain control module (PCM) detects that the revolutions per minute (RPM) difference between the rotational speed of the two sensors in Gear 1 falls outside the normal range.
• Common causes for the P0731 code include a defective gear 1 shift solenoid, internal transmission failure, and a defective speed sensor.
• Symptoms of the P0731 code include an illuminated check engine light, the vehicle not shifting properly, and decreased fuel economy.

You have eliminated the other possible causes. Looks to me like rebuild time.

 

I agree with Heyyou. you've lost the clutch pack or band.

 

No bands in this transmission, Fluid was almost new looking, nothing in the pan as I followed a recommendation on here and wasted a $1000 replacing the clutch pack and input/output solenoids, engine and Trans were replaced 85,000 kilometers ago, truck was only driven as a safety vehicle, never 4x4'd. Did what I should have done in the first place, took it to a,shop for another $200+, He said the " Pump Pressure" was wavering, can't be repaired, get a new Tranny, yet I've seen Tranny Pumps online for 45rfe for a couple of hundred ( probably US dollars) I'm in Canada...Not worth going to a wreckers as if this one failed 80, 000 kilometers later from Brand new.. Truck is in Immaculate condition, going to make a nice lawn ornament.

 

Lots of things it could be. Front pump failing, valve body leaking internally, bad clutches, clogged filter. Wrong ATF fluid, bad TCM or bad wiring between clutch pack and TCM.

 

O.K, so I found a 545rfe from a 2007 dodge ram 4x4 that had hit a Moose, from what I've read ( I'm now very sceptical) apparently it should bolt right up to my 04 Durango 4.7l 4x4, please tell me this info is correct, Very low kilometers, can't beat the price, apparently the seller just wanted the engine, Thanks.

 

45RFE and 545RFE are physically the same.

 

Yep, 45RFE became 545RFe through a software update (2006?) applying 2nd and 4th at the same time (I believe) to make 5th. Then another software update in 2012ish added second prime as a full time ratio to make it a 6 speed, 645RFE.

 

Will I run into any issues with my TCM do you think???

 

If so, can my tcm be adjusted/re programmed??