Hi all , I know this was discussed before , My 18 year old daughter came back tonight with my ZJ and I had to make a run to the store . I noticed the jeep not shifting outta 1st . I had to pepper the gas pedal to shift to 2nd. Naturally my daughter admits nothing (it was fine when I gave her the jeep),
aside from that …what would you consider this 4.0 engine with 42 re ? transmission ?
Im letting it cool down , disconnect the battery , check the fuses and throttle valve (tv) cable .
thats all I can do without a scan tool .
speed sensor ? Governor pressure sensor ?
I just had it rebuilt 3 months ago , and letting a teenager drive to who knows where and how far the trip was … argh. reminds me when I was 18 . 
I would start with output shaft speed sensor. After that I got nothing.
What if she drove the Jeep in 2nd gear (shifter) without knowing it for a long time ?
Conclusion : took it my transmission friend … Junk.
we think she accidentally drove the Jeep in 2nd gear for a long time .
So she accidentally hit the gear limiter into 2nd?
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no , the floor shifter . ya know PRND21 ? well it was probably drivin in 2 for awhile with hi speeds and the radio blasting.
Hey , is these forums that we use here are for serious questions with a serious answer , or all questions ask , gets kinda remarks that pokes fun at some questions ?
Lol the last 2 vehicles I had before the Jeep didn’t have the PRND21. They all had the slap shift that you shift gears up and down. When I’m driving or stopped at a light in the jeep I’ll hit the stick by accident reaching for the coffee or phone knocking the limiter down a gear. I’ll catch it because you feel it not shift. I never pushed it but I’m sure there is some sort of safety that would kick it up a gear if you drove it way too fast. Technology brain fart 
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Yea I hear ya , back when I was flying Cessnas , there was no PRNDL either. Just forward at 160 miles an hour with a ceiling of 14,000 feet !
holding a gear shouldnt hurt a trans motor maybe as it was turning too many rpms. most likely the trans was going out regardless of what she did to it.
I was going to say the same thing. If the tranny fluid did not overheat then I don’t see the problem.
I think she shifted into 1st gear , or low and drove like a bat outta hell without realizing the rpm sound outta the engine screaming at her . kids nowadays plug thier phones into the radio, and crank up the volume . IDK ? was working fine before I gave it to her .
IT WILL REMAIN A MYSTERY …
POST NOTE : guess what Im doing this week end ? lol
just bought a tranny with only 135 K miles on it. almost a virgin .
Hate to tell you this but the 42re likes to blow up around 150,000.