2006 Jeep Commander Stuck in LIMP Mode HELP!

[NickT1271]

While driving my 2006 Jeep Commander with the 4.7L on the highway at 70mph the transmission down shifted to 4th and then proceeded to down shift again into 3rd. My pressure on the pedal didnt change at all and would not shift up. At the same time, the check engine line immediately came on. I proceeded to pull over to the side of the road and go through ur basic routine of checking the fluid, running through other gears etc and all checked out normal. But when put it D, it takes off from and drives in 3rd gear. After hours of research online I've determined that my transmission is in "limp mode". I have read numerous forums about this and apparently its a pretty common issue with commanders. Ive read all different types of issues referring to the transmission module, getting it flashed at the dealer, senors failing, poor wire connections. All the stories seem to be the "run around" of poor dealer service with no means of actual success. I bought my commander used with 28k miles on it and it now has just under 60k miles. Its used as a daily driver and I havent had a single thing go wrong with it (aside from the typical leaky sunroof which I've fixed). I love my commander and planned on getting an easy 200k out of it (as i do with most of my Jeeps) but from what ive been reading - the transmissions must be junk and it has me worried. Can anyone tell me what caused my commander to go into limp mode? Especially while driving at highway speeds? I have some mechanical background to know it must be an electrical issue but I havent found anything similar to my particular case. Please Help!
Thanks!

[robby]

There have been quite a few trans issues with the V-6 Commanders.
These use a Mercedes trans and the electronics are persnickity.

The 4.7 and 5.7 Commanders use a different, more truck oriented unit.
A fair amount of electronics, but any trans can fail. There have been very few failures of this unit.

Regardless, the first step is to disconnect the negative battery cable and then turn the key on.....leave it like this for 5 minutes or so........you are essentally rebooting the computer by dumping it back to its base settings.

After 5 minutes, turn the key off and take it out.....this assures it really is turned off and reconnect the negative.

Fire it up and see what it does......you are trying to see if there is a 'hard' failure, in which case it will default back to third and the CEL will reset.
There is however, a possibility the problem will disappear, meaning some electronic something that we will never know jammed up the computers logic and it responded.

Sounds like a half assed response but I'm serious.....this has happened before.

Good luck,
Rob

[NickT1271]

Thanks Rob,
I took it to the Chrysler dealer today and they said it was the valve body. They quoted me at around $600 for the valve body and $300 for labor. I went ahead and drove it home thinking I would take it to a transmission shop and see if they could confirm it. After getting home I went ahead and tried what you said and when I went to start it up again I noticed a loud buzzing noise coming from the transmission. Could this be a good enough means to confirm it is the valve body? A friend of mine is a mechanic and says it is easy to change out a valve body and he can prolly get the part itself marked down.
Thanks!

[robby]

There was a old service bulletin for this 06 unit regarding cracking of the plastic trans filter, causing a fluid pressure loss.......although the complaint is generally a late gear engagement, it is possible this same failure could make noise.

Did the code return after battery disconnect BTW?

I am inclined to have your contact very carefully inspect that plastic filter for any cracks in the body or tube.
If any are found, I'd recommend changing both filters (I recommend that even if there are no cracks) and buttoning it up for further diagnostics.
If the problem persists, you're only out about 5 qts of fluid.....then the valve body can be exchanged......yes, any trans guy can do this 'in car' repair if thats all it needs.

Rob