Archived transmission won't shift

[RCARON]

2000 2500 automatic with 185,000 mile

on the way to work today the truck would not shift out or 3rd gear. it stays in this gear from a dead start . i have it at aamco transmission this morning but they have not found the problem. he states that the engine computer is not communicating with the transmission.

anyones help would be appretiated.

 

[KatDiesel]

For some reason the truck went into "limp mode"... .

 

[RCARON]

the code that i read was po753

 

[RBratby]

po753 is the 3-4 shift solenoid/trans relay circuits.

 

[RCARON]

replaced the 3/4 solenoid and transduser as well as the relay, and the problem is still there. it is like i am in 3rd gear all the time.

 

[JLittle]

My truck did the same thing! I replaced the same parts with no fix, I then took truck to dealer and they replaced a wire going to the trans from the PCM and then grounded my trans too! it fixed it! if you want I can see which terminal they ran a wire from and to?

 

[DVR]

my 01 4x4 stuck in 3rd too. i had to manually shift it. thank goodness my truck has a bumper to bumper warranty through DC until 100k. it happened at 85k a few weeks ago.

the dealer listed the following as replaced on my work order:

TRANSMISSION TRANSFER PLATE

TRANSMISSION VALVE BODY UPPER HOUSING



i took them a b&m drain plug they installed free while the pan was down as well as a mopar transmission fluid filter. the warranty covered the fluid and gasket.

 

[RCARON]

jlittle, thanks for that information, i spent the last 3 nights under the truck chasing wires. if you can tell me which pin number it would save me from braking down all the harnesses back to the pcm. i have around 5volts current on terminal 1 and 4 of the plug that plugs into the transmission just above the pan, and continuity on all the other terminals except number one.

i appreciate any help.

thanks again

 

[RCARON]

i also should have mentioned that when i jump the relay (two large terminals) that the truck will run first,second and third gear, but won't shift out of third.

exchanged the relay and the truck stays in third gear. all circumstances i still get the po753 code.

 

[Jetpilot]

I would reccomend phoning Bill K. at DTT (866-504-4220). I realize that you do not have a DTT transmission but he is always willing to help guys out. Also they are on west coast time so it will be a few hours till they are open.



Doug

 

[TnLRacing]

You say you replaced the 3/4 shift solonoid, How about the Gov. Pressure sensor? Has this been checked?

 

[Jetpilot]

Did you ever figure out your problem?



Doug

 

[RCARON]

i did figure out the problem with the help of your friend Bill K at DTT. the original parts that the Dodge dealership sold me was not the 3-4 shift solenoid that i requested. they sold me another solenoid. not knowing any better i thought the items i replaced were the 3-4 shift solenoids.

Bill K at DTT had the correct dodge part numbers and even E-mailed a picture of the correct unit. he had me back on track in less than a two minute phone conversation. i purchased the correct 3-4 shift solenoid and installed it that evening and the truck is back in business.

that you for your reccomendation and to the other tdr members who responded.