A friend of mine gave me a 2006 4.7L Durango that had a few problems. The biggest problem is that it won't go faster then 30 mph. It will drive comfortably up to about 20-25 mph, but the engine just revs up from there and the transmission doesn't make any noises or jolts at all. I'm hoping this is just a sensor/solenoid problem. I had the codes read and it spit out 8 codes, 3 of which were transmission codes and posted below. The employee at advanced auto wrote them down in this order. I copied and pasted them from the code page to give some discription.

P0700-INTERNAL TCM
P0733-GEAR RATIO ERROR IN 3RD
P1790-FAULT IMMEDIATELY AFTER SHIFT

I later asked my friend what symptoms she first noticed. She said her employee's drive it and that one just reported to her one day that it wouldn't drive over 30 mph.
If anyone can provide any insight as to what I should try first, I would appreciate that. I have changed the front band and solenoids on my 46RE in my Ram 1500 by myself, so hopefully this fix does not require digging much further than that into the tranny. I am pretty sure that the transmission in question is a 545RFE.

 

I did some digging in the meantime and found some info. In Dodges, the code p0700 generally just indicates a problem. The next code read indicates the specific problem. In my case, there are two codes. P0733 indicates a snesor/solenoid issue, and P1790 can mean low transmission fluid, bad transmission pump or a bad reverse piston. I can't imagine its any of these, as the fluid is not low and there was no reported transmission noise before it stopped working. There is also no hard downshifting or any indication that the problem is mechanical. I'll keep researching but if anyone can add their experience (if relevant) I'd appreciate it.

 

There can be a number of things causing this problem, unfortunately, they are mostly inside the transmission case. You don't mention the fluid level, so verify that first. If that is good, it's time to drop the pan. I would recommend that you find the best transmission shop and take the Durango there. If you decide to do this your self, a common error is incorrectly installing the fluid filter. This can cause fluid foaming and problems like that. So can wires with broken insulation to the solenoids. There are many more things that can be wrong as well. When you drop the pan be sure to look for debris, metal shards in particular. If you find them, it might be wise to pull the transmission and go for a used replacement. Hope you find something simple.

 

I found the problem. After taking the pan off, the fluid looked good. No large metal shavings, just some screw pieces from the damage shown in the image. Now the question is, what caused this, and how do I make sure it doesn't happen again? I would assume that a clogged channel would cause a powerful buildup of pressure and is likely what happened. I may decide to open the valve body to investigate lateror just get one from the junkyard..

 

I've seen those piston replacement kits online. Is this a common issue? Also, does anyone know what causes this so I can prevent it from happening as soon as I replace the pistons? Thanks