A few weeks ago, my 2005 Liberty started taking longer to shift from 2nd to 3rd, 3rd to 4th, and 4th to 5th. It also would make a thump when it finally did shift. It continued to get worse each day and today it would no longer to to 4th or 5th gear unless I completely took my foot off the throttle when going downhill. I checked the codes and found the following: p0715 (input speed sensor) as well as p0733, p0731, and p1790.
The input speed sensor was failing to send a correct signal and this resulted in the other codes being thrown. The TCM relies on the input speed (as well as the output speed) to tell it when to shift. My Jeep dealer wanted $48 for this sensor, but I bought one at AdvanceAuto for $21.95. It took less than a minute to change it. Had to disconnect the weatherpack connector and remove one bolt (8mm head). Pull sensor out by hand (no tools required), insert new sensor, install bolt and connect weatherpack. Clear codes and give the TCM a test drive to "re-learn" the shift points.
