2003 ram diesel auto trans in limp mode, cant find problem

hi

im at my wits end here

all was ok,
i went on an hour trip all was fine,
left to head home and

-Starts off in 2nd or 3rd,
You can manually shift into first
-doesn’t go into OD or lockup
-OD light won’t come on or off
-no cruise control
-gear indicator only lights when in neutral or park, unless key is in accessory position then all light

Replaced:
Pr lockup solenoids “solenoid pack” 52118500AB
-governor solenoid 4617210
-prindle/neutral safety switch 56045489AC
-transducer solenoid 56028196AD

-adjusted shift cable
-adjusted safety switch
-checked and cleaned all grounds and grounded PCM
-left both batteries disconnected overnight to clear codes

-removed fuse block under hood and cleaned all connections,

-replaced the TCM , it was flashed to the vehicle

its not throwing any codes

any new ideas?

Possible TPS. I had my TPS go out but it threw the code and acted all kinds of weird.

No idea from me, Tony as I finally sold my tranny problems down the road after three years of nightmares. I had tons of issues with the overdrive after the trans was rebuilt, even bought a new unit from Chrysler and still had issues. Got tired of having it towed home, it went to a guy who makes plow vehicles for his business...

TPS ??
throttle position sensor?

and what kind of weird did it act?

The throttle position sensor is hooked to the trans. with a cable. It's the big box thing in the front of the engine on the drivers side. It would limp, wouldn't shift, lock up converter at odd times. I don't remember if the dash indicator went funky though...It did throw the code and that TPS isn't cheap. How many miles on it?

All the same symptoms remain - no cruise, etc. or did some things change?

The no cruise is a good indicator of the computer seeing a code. Obviously you know about the key on/off 3 times thing...

Everything has remained the same throughout

220,000 miles

we did the key on and off 3 times

we also left the batteries disconnected overnight to clear any codes
'
ran it again and checked, no codes

My TPS went out at about the same 200,000 miles, mines an early '04 non HO.
Does the pedal feel funny under your toe? I could tell by the feel of the throttle pedal that all wasn't right.

Sensors can fail but may not set a code because they are still within a range the computer believes is a valid reading. For example, a temperature sensor that normally reads -40 to +300 degrees fails but still outputs a reading of -40. The computer interprets this as a valid reading and prevents the transmission from shifting because it is too cold even though the ambient temperature may be +70. Same with a TPS that is giving a reading of say 30% throttle all the time. The computer simply believes you are cruising and doesn't set a code even though the TPS reading never changes.

Sounds like there is not trans relay output voltage to the trans. Check to see if pin one of the black 8 way connector on the drivers side of the trans has 12V. Unplug it and check with the engine running. It's usually light blue wire if I remember correctly. If you don't have power check for blown fuse in the PDC, a bad trans control relay, bad wire between IPM and trans controller, or bad trans relay "control" wire between PCM and IPM. The IPM itself could also be faulty. If available, a scan tool would be helpful to actuate the relay. So you can check these aforementioned parts of the trans control system.

I agree I would definetly want to scan it. I remember on cars that I actually had bad clocksprings cause TPS problems which could cause the problems you have. Not sure how it will effect your truck without looking at the wire diagrahm. On some the 5 volt reference feed to the clockspring for the cruise switches also fed the TPS 5 volt feed and I had seen the clockspring under the steering wheel short voltage from the horn circuit to the 5 volt feed. I remember well because the TPS voltage reading on the scan tool was not steady and jumped around and read different then what I read on the 5 volt circuit with my Fluke Meter when I back probed the circuit. When I unhooked the clockspring the TPS read normal and everything worked fine other then the cruise and horn of course since I had the clockspring unhooked. Dont know if that could be your problem but a quick scan with the scan tool will tell you a ton about the circuits. I remember it well because the vehicle was sent to our dealer from a service station and the tech from the service station called me to ask me how the closkspring could fix the problem it had. He was a good tech as I knew it once he talked to me and he wanted to know why that fixed it ? Being I worked at the Dodge dealer I had more info for me to use then he did but a good tech always wants to know just how the part they put on fixed it and he went out of his way to talk to me and find out just what fixed it. Ron

My brother in law had this happen in his 2007 Ram. He replaced the transmission shift solenoid pack and all went back to normal.

thanks for all of your help and input

fortunately the problem just got repaired,

one of the terminal inside of the connector going to the TCM ,(on a diesel it only controls the trans, so its not the PCM) was corroded. even though the wire checked ok when probed, it wasnt until the plug was removed and taken apart (its a 2 piece plug, unlike our older cars use), and it broke connection inside of there

Its tough getting old

Glad you found it! Good job!

Overcrimped pins and a lack of strain relief will do it everytime.

Glad you got it fixed. Its actually still a PCM though as it does control some other items. Even on the gas eng truck with that same trans the PCM controls the trans overdrive & lock-up solenoids and the gov pressure. Ron