ronjenx

When the ABS/ESP becomes activated, one of the things it does is reduce the throttle setting, even if you continue the depress the gas pedal. With a reduction in throttle setting, I can't imagine the transmission would want to shift up a gear.
It all has to do with the JK thinking you are going into a skid, probably due to the steering wheel being a little out of alignment from the 5" lift. Could also be from a bad ABS wheel speed sensor lead.

This is all speculation on my part; I wasn't there to see what happened.