there is also a separate solenoid that engages the overdrive,
but I think it is sold as a package mounted on a bracket with the torque converter lockup solenoid

if there is a problem with the electrical wiring from PCM computer to the trans electrical plug, you can manually engage the overdrive solenoid by completing a Ground circuit with an electrical jumper once you get to 3rd gear

a bad ground connection can cause this problem.
Look for 'green death' colored crud at the various ground strap connections.
Older Rams are bad for this, and it can also mess up fuel tank level sensors and cruise control operation

it may have changed in later years, but for the 1995 model only the 2500 series Ram had the factory temperature thyristor sensor in the trans cooler line, although the wiring harness for the 1500 series had the unused plug for this sensor dangling near the top of the trans

 

Okay so where would this bracket be found? I traced all wires and only found the one solenoid and one sensor, there are two other what look like pressure sensors on a plate that these two plug into, I checked behind the plate and both sensors have a mesh filter behind them and seem to have pressureised ports behind them. Sorry Im new to anything electrical in a transmission. I can rebuild a T350 though.

second. If I just wanted to short it out, could you tell me what wire to plug into in the wireing harness outside of the trans or would I have to go in and tie into the wire on the solenoid itself??

Sorry for my ignorance but thank you all for the help

 

Wait, wait. You said you replace the O/D solenoid. The O/D solenoid and the L/U solenoid come together as part of the wiring harness. What have you replaced thus far?

 

got the O/D solenoid from O'Rileys and the governor pressure sensor from Bob Williams dodge in rome since nobody could get an aftermarket one. O/D was a metal part, pressure sensor was plastic wih a metal part that went into the valve body (99 transmission) they were both fairly close to each other and in the same seperate part of the valve body

 

according to the christmas manual *thankyou jebus* I have replaced the governer pressure sensor and the governer pressure solenoid valve

 

yes. You have not replaced the O/D solenoid. I was under the assumption that you replaced the o/d solenoid. That would be the next (should have been the first) place i would look, along with the O/D cancellation circuit.

 

Thats alright, thats what I had assumed I had replaced as well. Its what I asked for at the parts counter.

 

Hi... new guy here. I stumbled across this thread while looking for a part # of the governor pressure solenoid. I've got one that's dead, and trying to replace it for less than what the dealers around here... oh, enough of my problems.

Okay - so the trans won't go in to overdrive, except under special occasions. First, you need to determine if you're looking at a computer issue (i.e., the PCM isn't signalling the trans to go into OD), or a problem in the transmission itself.

To do this, take a normal SPST switch (use an automotive switch, the terminals will be easier to work with), wire one end to a good ground inside the cab (bottom frame of the instrument panel works). Leave the switch on the seat, and run another wire out the passenger window, under the hood, and to the PCM (passenger-side firewall). Look on connector #2 (the one in the middle), and find pin #21. It should be a brown wire. This is the OD solenoid control. Tap into this wire with the wire coming from the switch in the cab.

Now, make SURE the switch laying on the seat is OFF, then start the truck and get it up to highway speed. Flip the switch to ON. If the transmission shifts to OD, then you've got some kind of PCM-detected problem. If not, you know the problem is in the transmission somewhere.

If it's PCM-related, check your Throttle Position Sensor for proper operation. Check the output shaft speed sensor (screwed in to the driver's side of the OD unit on the transmission), though I would expect this to set a code if it were faulty.

If it doesn't go in to OD for you with the manual switch, you could have a bad O/D solenoid (you can test it with the same manual switch - probably need to have the pan off to hear it clunk (and the ignition needs to be on, of course) - and if it does, it will probably only clunk once - as it needs hydraulic pressure to reset it (or a good smack).

Again using the manual switch, you can do a pressure test to see (at least partially) what's going on. You'll need a100psi pressure gauge (normally, you do this with a 300psi gauge, but you won't be requiring that much pressure). The O/D pressure test port is located on the driver's side of the transmission, on the back of the main case, right near where the OD unit mates to the case. Plumb the test gauge in there, put the rear axle on jackstands (make SURE the vehicle is in 2WD, or put the front axle on stands, as well). Start the truck, and put it in gear. Normally, OD won't engage until you're in 3rd gear, but for test purposes, you can flip the switch and go in to "1st gear overdrive". You should see around 50-60psi. If you get almost no pressure, then either the solenoid isn't working, or is so weak that it can't hold back against the line pressure, or the OD vent in the VB is plugged up. If you get some pressure, but not up around the 50-60psi that you should, then you have an internal leak somewhere.

 

I would just like to say, that I love you for that last post.. Ive now replaced every electrical component in the transmission and still no shifting. I havnt driven the truck more than 20 minuetes at a time so I dont know if maybe ive made things worse and it doesnt shift at all now but its still not shifting regularly and thats my only grief. truck still runs flawlessly. I pulled a large steel bed car trailor with an S-10 with 2 small block V8's in the bed and didnt have one complaint from my truck. i just wish that when I was driving it regularly it would shift into O/D. of course normaly when Im out I take my car so *shrugs* if I find the problem I do, if not it doesnt matter much. at this point if somebody offerd me some money for it I might take it but it doesnt hurt my feelings to keep it around

 

Hi, I realize this is and OLD thread but I have just finished installing a 1998 47re in a 2001 truck and would like to share what I had to do to make the OD and TCC work. The problem was with the older gov press sensor (oval plug) temperature sensor works opposite than the newer sensor (rectangular plug). It would lock out OD because the PCM thought the fluid was -40*. I replaced just the plug for the gov prss sensor and installed the newer bracket that holds the gov press solenoid because it also retains the newer pressure sensor. Hopefully this might help someone having this issue.

Codey