ok guys got another question on this damn 95 12 valve auto tranny. so this morning my wife gets up and takes the truck to work which involves highway driving for 3 miles. she says it wouldnt shift into overdrive. so i take it out and sure enough it would shift 1 2 3 but not 4 or od. so i check the tranny fluid and its on the line between add and ok so i give it about a quart and a half to put it at the top of the ok section on the dipstick. again, i go for a drive and still it wont shift. so look underneath knowing that theres a sensor on the back of the tranny and one on the rear end that might possibly have somthing to do with such an issue and i find the one on the tranny looks brand new and who ever put it in had cut the wires fro the previous one and wired in a new connector in which the wires were just twisted together. so i clean em up and put some professional wire crimps on em. i also made sure the one on the rear end was good and i wiggled all the wires to and from both sensors all the way up to the engine. again away i went for a drive. i get down the road about 3 miles with out it shifting still and then it finally shifts 4 and then od. great! so i drive a few more miles and then stop and turn around. from stop it shifted 1 ......2......3.4.5. and it ended with me in od at about 25 mph. i also noticed that my speedometer now acts like its a tachometer at at 65mph it flickers back and forth.
sorry for the long story but i thought it might help with the diagnosis. gimme your best thoughts guys.

 

Dodge Trucks TechTran A500 42RH A518 46RH A618 47RH Service Manual check this out and see if it will help you brought to you by the muskrat

 

wierd... sounds like a computer issue even.... if you wanted to get rid of it all you can go to the computer and cut the wires then send a ground via a toggle switch to the two wires and you could control the 4th gear and TC lock up..... by the way these are 4 speed transmissions.... the "5th" is you TC lock up..... the wire numbers are Pin 54 for the TCC lock up control and pin number 55 for the overdrive selenoid..... i have mine set up this way but then again i have a gate shifter and a manual vb in mine so its needed.... hope this helps ya some

 

If the trans fluid doesn't get up to temp it won't shift into O/D.....also the trans shifts 1-2-3-OD-L/U.....So if the converter isn't locking up the TPS could be getting the wrong voltage or bad. You should feel he L/U at 45mph. But if the fluid isn't warm enough for the sensor then the PCM will hold the trans in 3rd until it warms the fluid enough.

 

this sounds like a great idea...so in return i would be able to go down the highway and determine when i want it to go ahead and shift into overdrive and tc lock up right? and if so i get the general idea of what to do but is there anyway you could get me some pics of where its all located and what wires to rig up?

 

Hey peeps, I got a '95 Dodge Cummins Turbo bout 147,000 miles, and when i got it , there was a slip. It was parked for 2 years before i got it.
Most times when i take off from a dead stop, and it also has slight trouble shifting between
2-3, kinda have to back off and force it to shift at a lower RPM.

Fluids have been ok, havent seen any pools of fluid on the ground.

Also i have heard it could be a shift sensor.

Dunno, first time diesel owner

any answers would help, I hope i dont have to re- build.

 

it shuld still lock up when its cold every truck i have driven would hit od and lock when it was cold

 

well it doesnt have anything to do with tranny temp cuz i have a gauge and it just wont go od or lockup even when its warm.

 

brindle, try out that TCC lockup switch - I've got one on mine as well. There is a writeup here somewhere.. Anyway, I'd also check out the TPS - sounds like it might be acting up.

 

its very easy to do.... all you have to do is get a switch... i have the rocker switches from autozone in mine..... you have to send a ground charge to the two wires on the ECM..... the ECM is located on the firewall of the truck near the Air Box on the passenger side..... you will have a big plug that has a bolt running it it (8mm head i think) remove the bolt and unplug the black piece (ECU plug) then take that plug and spilt the tabs on it and open it up...... on the side that plugs into the truck you will find numbers on the plug..... those are your pin numbers..... number 54 is your TC and number 55 is your OD.... using a wire tap splice into both of those wires and run those two wires back into the cab... then plug those wires into two seperate toggles or rocker switches into the output side.... then with the input connect it to a good ground (steering column).... i mounted my switches where the fog lights/OD switch is.... i shift OD till about 40-45 then hit the TC lockup after..... i have no pics right now cause my truck is in shop.... but i can answer any question bout this and can help ya out..... just let me know.....

hope this gets ya started and dont hesitate to ask me question

Dustin


in all seriousness your ECM might of taken a crap on ya for the controling.... but i would check your TPS and make sure the two plugs that are on that trans are connected and clean.....

does your speedometer work correctly all the time?