2001 Durango, 4.7L 4x4...so, 45RFE.
Started two days ago. Felt like I only had two forward gears and when shifting from neutral to D it would engage harshly. Threw codes for input speed sensor and 1st gear ratio incorrect error (0715 and 0731). So, yesterday I replaced both in and out speed sensors, TPS, changed both trans filters, and new ATF-4 fluid.
Resulted in same symptoms and threw the same two codes again. Today I drove it with a scanner connected and see it is shifting from 1st to 3rd, no 2nd when selector is in D. It will not downshift with hard acceleration. I can manually shift into 2nd, but can't manually shift into 1st...stays in 2nd even with selector in 1st. Verified what gears it was shifting into with the scanner (Snap-on MODIS Ultra), not just by listen or feel.
Line pressure was 120ish in park, 180-190 in reverse, and would increase from 80ish on up to 120ish when in D until it shifts. So, line pressure seems to be good. From what I have read, desired line pressure is pre-set around 120 while in Park and during shifts...so this is consistent.
So, with all that said. Bad shift solenoid pack and/or valve body? Should I replace the line pressure sensor? Browsing the internet I see mention of a governor solenoid and governor sensor. From what I gather the "governor pressure sensor" is the same as "line pressure sensor", located towards the rear of the pass side of the trans...correct? I am also guessing the "governor solenoid" is part of the shift solenoid pack, not a separate component within the trans...correct?
I need this to be fixed before Jun 17th -- driving from AZ to NY/ME, leaving that day. Any help would be MUCH appreciated!