After starting to move in 1st (auto trans) at about 10 MPH vehicle stoped ABRUPTLY. Moving again, same thing happened. Diagnosis: Transmission is shifting from first into reverse. Upon disassembly, the root cause could not be determined. Extensive damage requiring full rebuild. Estimated cost $3,200.00. Vehicle has 130,000 miles.
At 130000 miles, this transmission should have had the fluid drained and refilled at 50k and 100k, with ATF +4 only. Was this done?
I wonder if this transmission is computer controlled.
I wonder what he thought he was asking?
You didn’t mention the designation of the transmission so I am assuming an A727 preceded by an overdrive.
Anyway, on most automatic transmissions, the reaction element for first gear is taken on a one way roller clutch or sprague clutch. If this clutch gets jammed, the transmission will lock when it tries to go to the next ratio.
You don’t mention if the transmission was making metal. If the debris in the pan drop had a lot of filings of various metals, instead of fiber dust, the transmission would require a major overhaul including a torque converter and major mechanical parts. So you might as well go with a completely new unit and start over.
Let us know the exact model of the transmission and the nature of what was found in the pan.
Don’t assume. The 727 has been out of production since the 90’s. Well before this Durango was built.
Likely a 42RLE or 45RFE, or a 545RFE dependig on 2WD or 4WD, 4 or 5 speed automatic.
Sorry I am a little behind in my research. I will look up those transmissions and determine the reaction element and method of holding. Maybe get a core example of each and go exploring.
Sorry for leading “DH43” astray.
On further research (thanks “Mustangman”) I have found that the 42RLE does not have a one way device for low. The 45RFE and the 545RFE do have a one way device that Chrysler calls a ‘mechanical diode’. Anyway, all three a low/reverse clutch that is pressurized by a three way PWM hydraulic valve commanded by the TCM. If this valve is stuck or commanded in the ‘ON’ position the low/reverse clutch will remain ‘ON’. When the TCM commands the 2/4 clutch to engage the rear planets will lock causing the transmission to lock up.
I hope “DH43” returns to this post to find a possible answer.
If you aren’t sure of the diagnosis, you can always tow the vehicle to another transmission shop for a second opinion. Ask your regular mechanic who’s the best tranny shop in town.
I expect the diagnosis is correct, and you have three options
- rebuild this transmission
- purchase a rebuilt transmission
- purchase a used transmission from a crashed Durango , where the accident damage didn’t likely damage the transmission.
If option 3 yielded a transmission from a low mileage Durango, and the price was right, I’ld probably go that way myself.