Does anybody know if the PCM controls the Auto tranny on a 1997 2500? Do see the whole story please look at transmition wierd? thread.

THANKS FOR ANY HELP I CAN GET!!!!!!!!

 

I can't tell you for sure on a '97 but I had PCM/tranny trouble with mine.

Long story short, bought it used at auction and noticed it didn't start out in 1st gear. I'd put it in drive and it started out in 2nd, shifted into third, then no overdrive. Found out later it was the PCM.

 

Mine is doring that too. Except If you have to set a a stop sign for about 30 seconds or longer you can feel it shift down into 1st. Then it will not up shift, sometimes it gets stuck in 1st or 2nd untill you pull over put it in park and then back to drive. Tonight the hole truck died like it ran out of gas, but it started right back up. Then I losted every gear even park. I shut it off and started it back up and I had gears, but now it will only come out of 1st if you drive it like a stick and sometimes even then it will not come out of first. It was slipping when I backed it into the garage.

 

Read back over your "weird tranny" thread to refresh my memory.Seems like if it was the PCM, the problem would be consistant, or at least it was with mine. Yours is doing all sorts of things. Maybe more than one problem.

What ATF did you use when you changed it? Was there any metal or plastic in the pan or filter you could notice?

 

I believe the '97 and older have nothing to do with the PCM. Even with a '98 or newer the PCM only shifts controls overdrive and the torque convertor lock/unlock, so 1st, 2nd, and 3rd gears still have nothing to do with the PCM IIRC.

 

I was told the same, also the PCM monitors tranmission temp.

 

I used the recomended ATF from the Dodge dealer. There was not any metal or plactic in the filter or fluid except by the magnet, but no piceces. My plan is to drop the pan next to see if there is any now. The code I got from the check engine light was po740 Torque converter clutch no RPM drop at lockup.

Ramdamit98 Any idea what else could be the problem with the clutch lock /up system? IE. Is there a sensor or something?

 

PCM on a '99 must control the tranny. Mine at purchase had no 1st gear, would only start out in 2nd, then shift into 3rd, then no OD. Ordered a reman PCM, put it in and had 1st gear for the first time (whoo hoo!) but then with no other gears (Awww mannnn!!!). Later found out the wrong PCM was sent. It was for a manual tranny. Got the correct one and it ran through all gears!

dodge@1997 - good there was nothing in the pan and you used ATF 4 . I'm limited on trans help so hope someone can help you soon!

 

looks like its time to take it to the tranny shop bigun...

 

Not exactly. Up to '98 4xRH's were used....rear/hydraulic. '98 up were 4xRE's....rear/electronic. It's still valvebody controlled, but in the RE's the governer pressure is controlled by the PCM (PWM solenoid i think). RH's used old-school governor controlls. OD/lockup circuits are solenoids on all of them. Only thing is I'm not POSITIVE that it was 98 that they switched to RE's....thought it was 96, but the 2-minute search i just did disagrees with that.