I have a 1996 Explorer XLT with a 4 speed auto that won't shift into overdrive. The od light flashes and I had codes P0755 & P0756 on it. I was told the transmission was rebuilt less than 15k ago. The book I have says solenoid B malfunction on P0755 and solenoid B stuck off for P0756. Which solenoid is this referring to and is this most likely the problem? Any help would be appreciated.
P0755 is "Shift Solenoid No. 2 Circuit." This means electrical malfunction was detected.
P0756 is "Shift Solenoid No. 2 Performance".
I don't have the info. for 4R44 or 55 transmission, mine is later, that's why it numbers the solenoids instead of using letters. The solenoid involved is the same, though. Shift Solenoid "B" or "2" causes the transmission to shift into 3rd. gear, not 4th (overdrive). What makes you feel you are not getting into overdrive (4th. ) gear?
When solenoids go blinky and the PCM detects it as electrical failure-caused, it's usually just that. Mechanical failures within the transmission are harder to pinpoint, thus while trouble codes are a wonderful tool, they are not infallible.
If the trans. WAS rebuilt 15K ago, the solenoids may NOT have been replaced, thus failure is possible. Your transmission has individually-replaceable solenoids, so, for a hundred bucks or so, a replacement solenoid given the circumstances, is likely a good bet. BUT, first, it must be clarified as to whether or not
3rd. GEAR is engaging. imp