Regearing '14 JK - or any other vehicle?

[tbburg]

This last weekend I was talking to a dealership mechanic friend who had just completed a gear change on a 2014 JK. When he took it for a test-drive, it threw a code and set off the check-engine light. Several hours of research and testing showed that the problem was a discrepancy between the driveshaft (transmission output) speed and the axle speed - as measured by the ABS sensors. There is a way to specify gear ratio in the factory computer, but it is limited to factory option gears.
Apparently there are re-programmers available that will hack the factory settings.(Probably voiding the powertrain warranty.)

The discussion ended with us both wondering if this was JK-only, Jeep-only, or something industry wide. Any experience with re-gearing modifying the powertrain on a new vehicle?

 

[Hellbent]

we do a lot of re-gears where I work. the newer jk's are super finicky, you must recalibrate the jeep (we use the aev procal mostly, superchips makes a good one too) or you will have nothing but trouble.
we never really have any issues except with 12-up jk's and later model Chevy's. they just won't tolerate any gear ratio and/or tire size changes without correction.
otherwise you get lights, bells, weird shift points, esp system going nuts, etc.

 

[Dundy]

/Thread. Hellbent's got it right. The PCM needs to have everything match or it'll freak out.

Hell, after performing a budget boost to the new JK's the steering wheel is a little off. It needs to be absolutely straight in order for the traction control to be happy.

 

[Bryan C.]

The auto trans in the 2011 and up JK is a chrysler built mercedes transmisison. The mercedes trans controller is a finicky bastard. Even when completely stock it is a pain in
the ass to deal with.

 

[XJLI]

Hell, after performing a budget boost to the new JK's the steering wheel is a little off. It needs to be absolutely straight in order for the traction control to be happy.

wow really? is there a steering angle sensor for the traction control in JKs?

 

[Dundy]

wow really? is there a steering angle sensor for the traction control in JKs?

Yupper!