January 12, 201510 yr P0234 is an overboost code. It may have come when you put your foot into it to get the transmission to try to shift (if that is what you did). More than likely the waste gate is rusted. Does your truck start out in first gear then shift to second normally?
January 12, 201510 yr Fill out your signature with the mods and details. It will help us out. IIRC. It is common to have the overboost code with a boost elbow on the turbo also and no boost fooler or programmer on the truck. Edited January 12, 201510 yr by CSM
January 12, 201510 yr Howdy Guys, Well I've been trying to help 8181 with this issue in the chat room, and frankly, I'm not a 47re expert. But here are some details he's given me. Bought it new, completely stock 2001 Dodge Ram 2500 automatic , won't shift out of third gear. Was on and off problem. Put in N then drive and would shift today I drove home at 2700 rpm and going maybe 55. Shifts manually, but not in drive. On other days it down shift to 1st when it should not. Like at a roundabout Tommrow it may work fine. It's been doing this for a couple of months. But this is the 1st time it won't go out of third. Hopefully someone a little more auto savvy can chime in. Thanks!
January 12, 201510 yr I sound like a scratched record here, but my first go to with weird automatic behavior is to check the alternator for noise. I am not an automatic expect here though.
January 12, 201510 yr Owner I'll say Tom's right on the P0234 code. As for the transmission shift issues I would say it governor pressure solenoid and sensor. (Educated guess) I'm also not very good with 47RE trans. But welcomee to Mopar1973Man.Com
January 12, 201510 yr Author I took out 140 amp alternator fuse and went for drive, did a lot of weird things. I put fuse back and inspected alternator. I touched the cable that goes from back of alternator to the battery and it started sparking. I disconnected from alt and where it is routed over alt housing I looked at under side of wire and it had rubbed through plastic and wire was shorting out on aluminum alt housing. Half the strands were broken and they were green colored. I've been having shifting problem for long time and it looks like this wire has been worn open for a long time. But it must have been charging or because never a starting problem just shifting. I don't have a new cable so I'm going to tape out melted area hock back up to alt clear codes and give it a try. I
January 12, 201510 yr Author Thanks for the welcome. I have just been a visitor and have resolved a lot of issues just reading the forum topics. Thank you guys for all the previous help.
January 12, 201510 yr On other days it down shift to 1st when it should not. Like at a roundabout This is indicative of the Output Speed Sensor on the side of the transmission. The sensors are not expensive, but I would check the plug first. Try pulling the plug and twist the wires a couple of times and plug it back in with the wires still twisted. If that fixes it then you can get a new plug and replace it. For some reasomn I can't seemto find an image that this software will allow me to post, but if you look here the white plastic ones are the sensor: https://www.google.com/search?q=47re+oss&source=lnms&tbm=isch&sa=X&ei=0OyzVPH7MdWqyASGr4DYBQ&ved=0CAkQ_AUoAg&biw=1600&bih=761
January 12, 201510 yr Author Thank you very much. I just got home with my new multimeter. I'm going to test the alt for diao damage as suggested earlier. I'm hoping for the sensor though the alt are over 200. Thanks again.
January 12, 201510 yr Author I tested the alt and got 14.72 do volts . I don't have the same meter as one in picture but put dial on 2 in the V with the wave line and got .028 so if I did this right it's craw under truck and check plug on sensor. I hope it does not snow.
January 13, 201510 yr You can also take a look at this page and see if it helps: http://www.dieseltrucksite.com/showthread.php?t=897
January 16, 201510 yr Author Thanks everybody for your help. I had to go to town and took my truck and two miles out my wheel almost fell off. A concerned citizen gave me a ride home and I called tow company and had it towed to local garage. I told them about trans and the educated guess from moparman and a rotor, wheel bearing governor pressure and sensor fluid and filter. Everything is well it goes down the rode and shifts and my wallet is 900. Lighter.
What to do. Does not shift out of second gear