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Discussion Starter #1
well its been to the tranny shop and they replaced some solenoid (i know the guy, does great work so i know the job was done) but its still farting on us.

starts out in second, thinks its shifting into second from first, but just goes back into second and slams into gear. feels like it has a shift kit in an old muscle car. anyone else had this problem at all???
 

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not sure, does the heep auto use a vacuum signal to modulate shifts? if so then you might check for vacuum leaks.
 

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Discussion Starter #3
hmmm good question, i dont think so. plus no codes coming up and no vacuum "pssssss" leaks
 

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Your transmission is likely going into "limp mode" and that is what is causing the hard shifts. This COULD be why it is starting off in second as well.

I will admit that I am not very familiar with Jeep auto trannies or OBDII systems. On OBDI, you can have fault codes without a CEL. It might be worth your time to have codes pulled, just to make sure the system is clear. Autozone etc will do this free fo charge.

Many times on an electronically controlled transmisison, it comes down to just a few possible issues.

1. Dirty electrical connections. I would unplug everything from the tranny and clean it thoroughly.

2. Shift solenoid pack - which it sounds like was replaced by a reputable guy. I do wonder how he came to that conclusion though. Did he use any transmission diagnostic tools?

3. TPS. If the engine doesn't know where the throttle is vs. load, then it can't determine when to shift.

4. VSS. If the vehicle doesn't know how fast it is going or is getting faulty/bad signals, then it won't know when to shift.

5. Your shift position sensor, commonly referred to as an MLPS.

I wrote this thread for fullsize Ford Trucks about a year and a half ago. The EEC-IV codes will not apply to you, but the basic principles of transmission diagnostics may help spark some thought. Give it a read and hopefully it will point you in the right direction. In any case, i hope it isn't internal.

http://www.fullsizebronco.com/forum/sho ... p?t=122096
 
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