As many of the members of W.L.B know I had to have the transmission rebuilt in my 2006 LJ. A month later and less than 1,000 miles on the new transmission it started shifting badly between first and second when it was "cold". What I mean by "cold" is if the jeep sat overnight or even if it sat for several hours. After the jeep was driven a few miles and went through a couple shift cycles it would run and shift fine. I took it back to the trans shop for warranty work. They looked everything over and the trans seemed fine but the felt the bad shifts that I was feeling so the had one of their top techs get on the job. After looking into it the found that there is a "known" problem with the PCM's. It will not show any codes but is natorious for being faulty and causing shifting problems. I got online and researched it some and see a lot of people who went through a lot of money replacing parts, sensors and transmissions only to have the problem return. What seemed to cure the problem was a new PCM from the dealership (not one from an online store). This morning after my jeep was "cold" the tech hooked a scan tool up to my jeep and drove it. Of course it shifted badly and showed up on his scan tool indicating a bad PCM. Like I said, there is a lot of stuff online if you search but figured I would post here also so nobody has to chase a ghost thinking they have a trans problem when in fact it is a PCM problem.
Another reason why I think I am going to like rowing my own gear selector in the new LJ
Glad you got it figured out.
I miss my old 5 speed with the stroker more and more every day :( This soccer mom jeep (sorry Paul) just isn't cutting it right now. I love the ride quality and extra room but this whole transmission and PCM thing has me a little hot under the collar right now.
1. put in neutral and push out into traffic
2. collect insurance money
3. go buy a jeep with a manual like god intended in the first place