Issues taking off from stop.
Hi ya'll! Long time reader first time poster. Need some help from those that have experienced this or from transmission gurus. Just picked up my second Expedition with some transmission issues for cheap. 98 Expo, 4.6, 4x4, 4r70w, 160k.
Symptom: When vehicle is driven cold to about 20 minutes of city driving(under 50mph), vehicle shifts into all four gears, drives awesome and no issues at all. After 20 minutes, taking off from a stop vehicle feels like it's in neutral unless you apply very very light throttle but if you do that, it then feels that it'll try to engage, move 1-3mph then pop out again. While this happens, if you put the shifter into 2 or 1, or manually shift between positions 1 and 2, truck takes off and drives no problem in those gears. Leaving in D ONLY with o/d on or off will exhibit any "slip" or no drive(just revs).
Fluid level perfect, fluid slightly darker than new. Have not dropped the pan yet. Shifter cable installation looks good, no abnormalities were found with trans wiring harness, shifter cable. Vehicle speed sensor operates normally. Engine does not misfire nor store any related codes in PCM.
After reading up, decided to throw a new MLPS at it. No faults stored in PCM before replacing. After 30 minutes of driving, did the same thing. Drove back home 45 minutes on city streets manually shifting, then o/d light started flashing. Trying to put back into D, vehicle now drives normally but shifts more firm and take off has a slight slip before engagement, but moves and shifts nonetheless.
My guess is a limp mode= full line pressure type of deal, but I don't work on Fords, just love and drive them.
My question: Is this worth trying to drop the pan to check the wiring harness and/or shift solenoids or am I just looking at the wrong thing? Or should I just throw a new unit at it? Also, are transmission trouble codes/fault memory stored in PCM?
Any help would be appreciated! Thanks for reading folks.
Hi ya'll! Long time reader first time poster. Need some help from those that have experienced this or from transmission gurus. Just picked up my second Expedition with some transmission issues for cheap. 98 Expo, 4.6, 4x4, 4r70w, 160k.
Symptom: When vehicle is driven cold to about 20 minutes of city driving(under 50mph), vehicle shifts into all four gears, drives awesome and no issues at all. After 20 minutes, taking off from a stop vehicle feels like it's in neutral unless you apply very very light throttle but if you do that, it then feels that it'll try to engage, move 1-3mph then pop out again. While this happens, if you put the shifter into 2 or 1, or manually shift between positions 1 and 2, truck takes off and drives no problem in those gears. Leaving in D ONLY with o/d on or off will exhibit any "slip" or no drive(just revs).
Fluid level perfect, fluid slightly darker than new. Have not dropped the pan yet. Shifter cable installation looks good, no abnormalities were found with trans wiring harness, shifter cable. Vehicle speed sensor operates normally. Engine does not misfire nor store any related codes in PCM.
After reading up, decided to throw a new MLPS at it. No faults stored in PCM before replacing. After 30 minutes of driving, did the same thing. Drove back home 45 minutes on city streets manually shifting, then o/d light started flashing. Trying to put back into D, vehicle now drives normally but shifts more firm and take off has a slight slip before engagement, but moves and shifts nonetheless.
My guess is a limp mode= full line pressure type of deal, but I don't work on Fords, just love and drive them.
My question: Is this worth trying to drop the pan to check the wiring harness and/or shift solenoids or am I just looking at the wrong thing? Or should I just throw a new unit at it? Also, are transmission trouble codes/fault memory stored in PCM?
Any help would be appreciated! Thanks for reading folks.
Last edited:
