Hello I'm Jason nice to meet you guys/gals. My buddy is working on a 2001 Durango 4x4 5.9L with a (focked up) transmission. He received the truck and the owner says it needed a new trans. b/c it was slipping through all the gears. The fluid high on the dipstick. But the owner insisted to change the transmission. So we changed the trans and now it stays in 2nd gear (it might be 3rd but we think it's 2nd). Is this a PCM or TCM issue? Is there an actual separate TCM from the PCM or are the combined into one unit?

What is the next step here?

Jason

 

there is no tcm on the 5.9l engines, that was only used on trucks w/ the 45 and 545rfe transmissions (4.7l engines), first thing i would do is try shifting the truck manually thru the gears

our local transmission expert is a user known as Master Tech, im sure he will chime in soon, if not feel free to pm him and he will be able to point you in the right direction

 

Shrp,

Can't shift manually through gears.

 

Sounds like you are requiring a band adjustment pretty bad. When was the last time the bands were adjusted, and when you say you can't shift manually thru the gears, do you mean it doesn't shift or you literally can't move the gear selector?

 

the selector moves but doesn't shift into gears... I just reset the PCM by unhooking the battery and holding the key in the start position for 30 sec.. then I test drove it and it shift fine until I stopped then it wouldn't shift out of 1st.

 

ITs not throwing any codes

 

It seems to me that it's either the PCM or the new Transmission causing the transmission or stay in 1st after it stops. What would cause the transmission to tell the PCM to stay in 1st gear after it was reset and shifted fine until the first stop sign?

 

I'd just make sure the valve body is clean. If a shift solenoid was bad it would most likely throw a code. If it's stuck in 3rd gear, it's in limp mode for one reason or another.
Also where did you get this new tranny? rebuild, new, used? And make sure you're using the correct fluid in it too, the wrong type will cause some whacky problems.

 

The tranny that's in there now is from a junk yard. Is 1st gear a limp mode?

 

3rd is.

I'd pull that valve body and just make sure it's clean for peace of mind. It's either that or eletrical, transmission seems to work just fine since all is good untill it needs to downshift.