Engine/Transmission (1994 - 1998) Trans Issues

[budnate]

ok, hang tight till tomorrow, it's friday loading up to go salmon fishing in the a/m it's go time, I will shoot pics and exsplain it all tomorrow.



Peace, B.

 

[PToombs]

Cool, thanks. And have a great time fishing!

 

[budnate]

OK, here is what I have going on, locate the middle plug find the solid Orange wire, its tight behind the airbox... I went ahead and split open the harness up near the top of the air box, I cut the wire and have been playing with resistors..... its really a pain, my radio schack has a crappy selection and our good electronics place moved 20 miles away to get out to cheap rent a I guess... anyway I am ordering a "0 to 250 ohm potentiometer" and be done with it,

250 OHM LINEAR POTENTIOMETER | AllElectronics.com



I already have the pair of 16 gauge pulled from there to back up under the dash on the left, just score a pot and twist a few times find the sweet spot with your meter and be done..... its my belief if the voltage is drifting now on our trucks, its going to keep on doing it, so eventually the resistor will not work, with a pot you can set it real quick with a meter and forget it again.



you can see my Mickey mouse resistor deal I have going now, testing, anyway back your voltage back down from 5vdc and see when it stops over volting... . keep in mind the lower the volts the higher the line pressure, which to most guys is good, but your trans may hit the gears to hard like mine, I need to raise my voltage signal a tad. if this dont make sense just yell.



peace, B.





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[PToombs]

Ok, that looks pretty straight forward. The potentiometer looks like a better idea too. I'll try to get parts tomorrow and play with it.



Is it ok to drive this thing if I shift to 1st to start out? I was going to a tractor show tomorrow and wanted to take the kids, so I need the bigger cab. I haven't driven it because I didn't want to hurt it more.

Thanks,

 

[budnate]

up to you, mine was pretty wierd and felt like it was really loading and slipping to get going even manually shifting, all I could imagine was the clutch pack taking a beating, and that solanoid not opening and cooking the fluid.



if it was mine I would hitch a ride with a buddy.

 

[PToombs]

I didn't drive it, took the good truck. I worked on it sunday, and got rid of the temp sensor code only the 1st time. It says the trans temp is 302 degrees and the truck hasn't been run for 3 days. I gave up temporarily, the FSM will be here on wednesday. (allegedly) Then I can check wires for continuity and the sensor and stuff. Too hot to do anything after working in it all day anyways.

(Insert beer smilie here)



I also need to track down the air leak in the fuel system too. That's frustrating also, but that's a whole different thread! :-laf

 

[budnate]

stick with it man, I fully understand and feel your pain my truck got a attitude and I have had to touch almost everything on it in the last 6 months and still working on little stuff now, for some reason the universe has required I know the inner most workings of this truck thoroughly, definitely miller time.



Piece, B.

 

[PToombs]

I can't drink on this job. I get so frustrated that would I get drunk, fall down, and can't get back up. :-laf

I'll keep you updated. Need to read the FSM some and figure stuff out. It's quite a bit different than the one for my '92.



Oh, and I think I found the air leak too. I'll know for sure when I get home tomorrow and see if it starts.

 

[PToombs]

Ok, update! I tried several resistors, and had it down to 2. 21 volts on the orange wire and it still showed codes and high temp. I unplugged the wire from the trans and it didn't change anything. Still showed 302* and 4. 98 volts. I checked continuity and no wires are shorted to any other. The thing I noticed is on 2 wires, the light green/ white to terminal 4 at the trans (gov pressure signal) and the purple wire to terminal 8 which is the trans sensor, show 5 volts. If I'm reading the FSM right, there should be no voltage on these, they should be the signal return to the PCM . I thought about cutting the wires and putting the resistor in the temp wire. I just don't want to cut a bunch of wires though.



Right, wrong, or ideas?

 

[budnate]

Pete, now that you can control the voltage to the trans you need to replace the solanoids then tune it shoot for around 4. 60,70dc to the trans after the resistor and see what happens, or buy the volumn pot and stop pulling hair,



if your clearing the codes and have the voltage that low and still throwing trouble codes that tells me there puked from over voltage allready, mine did the same deal till I stuck new stuff in.



I found a wholesale trans place it was about $150 for all 3 items, I would give you the numbers but this place is a mess and I can barely find my azz, let alone a reciept from 2 months ago, lol .



remember what Red Green says and stay the course.

 

[PToombs]

Bud, is there supposed to be power on those 2 wires? I also get high voltage reading with the trans not plugged in and the transmission temp says 302*.

I was going to take the scanner and plug it into my buddies 24v 98 and compare the 2. Maybe pull the plug and check voltage at the trans too.

 

[budnate]

I am new to troubleshooting these transmission's that's for sure, like you it smacked me in the face so I had to work through it, all I know Is what I was able to find here and there on the boards and talk with a local trans guy I know over the phone. . not much help... and I do lots of low voltage control system work in hi rise buildings... . I never unplugged the trans and tried to run the truck,



didn't you say these solenoids are out of used trans you have? if so I would not have any faith in them being good, I know its a hard bullet to bite, the way I looked at it was if the trans does need a rebuild its one less thing I needed to buy. and if it was working fine and out of the blue started the limp mode its all electrical giving you the grief on this go.



why your reading the codes even unplugged sometimes stuff is engineered to remember its last state and hold till its powered up again or when a device fails it will freeze its last reading until the device starts talking to the computer again... it gives the computer and systems something to reference and move on, if that make sense? do these Dodges work like that I dont know for sure, but probably pretty close its a basic logic system.



the orange wire should read the same V at the resistor and the plug at the trans, not sure what signal V or? comes back from a solenoid to the computer never had to go that far.



sorry not much help today, stick with it.

 

[PToombs]

Ok, found a definite problem. Oo. I was reading the FSM and wondering about the power on those 2 wires when it hit me in the chops, those are feeds for the sensor, not returns. Just like a fuel guage, power goes down, then the switch, (potentiometer of some kind in most cases) changes the resistance on the wire. I put a resistor in the trans plug and put the other end to ground, hooked up the scanner, and checked the voltage. Scanner said I was down to 2. 6 something volts. Cool! Then I figured out what was supposed to happen, so I was checking the continuity on the sensor wires and they were ok. Then I suddenly realised there was no ground. So back to the FSM and I found it. The ground goes to plug C3. So I pulled that from the PCM, plugged the trans plug back in and tried continuity again from sensor terminal thru trans to ground terminal. No connection. I have a bad connection in the trans some place. I had to put kids to bed so I was done for the night.

Tomorrow I will pull the VB on the spare trans and see where the wires go while the other one is draining.

Progress!

 

[budnate]

cool,on standby.

 

[PToombs]

Aww, Bud, that's cute! :-laf I got the e-mail notification so I never looked and just saw the pic now.



And I found the problem. The idiot that was in the pan last didn't hook up the sensor plug. On the other hand, this most likely saved the sensor from the over voltage. I had the resistor in with alligator clips and put the scanner on it with the pan off. I had 4. 70 volts after the resistor. 680 ohm resistor. Temp showed 72* which is about what it was here, gov pressure was 0, and no codes. I'm going to the electronics shop tomorrow or the next day for a potentiometer to put in. I still have to put the oil in, but I'm going to try to drive it tomorrow to see what happens. Oo.

 

[budnate]

allrighty, report back later.

 

[PToombs]

Ok, took it for a drive. Didn't even get out of the driveway and it was in 2nd again. I hooked up the scanner and left it in. Had a P0748 (or something) code, open or short to gov solenoid. Code wouldn't clear. Shut it off and back to the multimeter. I double checked the spare harness on the bench and then the truck, and it was ok, no open, no shorts. I plugged the PCM back in and started it, and had a 3-4 shift code too. I used the scanner to clear and they didn't come back, So I went around the block. The truck seems to shift a little soon, but I know the TPS is off, that's the next mod. 2nd is fried right out of it, it slips in and takes it's time to do it. Other than that, it might be driveable until I can get the spare rebuilt. I was going to put in a potentiometer, now I might just solder in the resistor and call it good. I'm not sure yet. Tomorrow I'll try to button up some of the other stuff I have apart and drive it for a few days.

Wish me luck! :-laf

 

[budnate]

bummer, make sure your tv cable is nuts on also, it controls line press as you drive if its off it can give the slip sensation.



peace, B

 

[PToombs]

Ok, I think it's right, but I'll double check it. Much easier now with the FSM.

 

[PToombs]

Ok, I checked the voltage after the resistor with the truck running, 4. 28 volts. I thought it was kinda low so I went to radio shack and got a potentiometer. I tried that and it didn't seem to drop the voltage at all, so I just soldered the resistor in and called it good.

I drove it for a short ride yesterday, and a longer one today. It shifts as well as it can for the 2nd gear clutches being fried. It takes off normal in 1st and shifts up thru pretty good. 2nd just kinda slips in there and takes it's time about it, but I can live with it for a while. The converter seems sloppy as all get out too.



Thanks to Bud for babysitting me thru this ordeal. At least now I have a better idea what goes on in these trannys so I can figure out future issues and help others.