Oh well!

[GPster]

Went for a ride in the truck I now own with our new (to us) dog to pick up my new glasses. Noticed when I was leaving town that the one-two shift on the automatic transmission in the truck ("03 Ford Ranger 3L v6 157,000) was more firm/harsh than usual. Noticed the OD / off light on the dash was on. The previous owner of the truck had told me that had happened to him occasionally and if he shut the truck off when he re-started it the light would clear. That has only happened to me 3 times in the year I have owned the truck. We got to our destination and shut it off. When we were ready to leave the light had cleared so everything was OK. On the way home the light must have came on because when stopping and starting to roll again I got the firm/harsh 1-2 shift again. This shift has not been a part of the "light on" situation before and this situation has never occurred while driving and the light was off when I first started. What should I add to my Christmas list? GPster

[kb426]

I found this:
http://www.ford-trucks.com/forums/585150-4r55e-5r55e-ranger-explorer-transmission-problems-click-here.html

[wayne petty]

plug in an OBD2 scan tool...

gather all the codes..

post them here..

get into the live data stream..

look at the  what do they call it..

shifter position.. see if in park a P shows up.. Reverse that a R shows up neutral that an N shows up.. you get idea.. PRNOD D 2 L.. something like that..

its a major issue on higher mileage ford trucks.. the manual lever position sensor changes voltage to the computer and can get glitches that will make the shift harsh.. please read instructions before attempting to replace it..

you don't want to ruin your transmission..

please also .. pick up your digital volt meter and run the voltage drop test..

engine running.. headlights on..   digital meter set to 20 volts DC>.

1.  Negative battery post to the positive battery post.. 14.1 to 14.8 volts is expected..

2. Negative battery post to the engine block.. 0.04 volts DC max..

3. Negative battery post to the body.. 0.02 volts DC MAX..

4. engine block to the body.. 0.02 volts DC max..

if you get more than the 4/100ths or 2/100ths of a volt on the last 3 tests.. you have a bad ground.. getting right at that fraction shows that at least the 3 main ground wires are intact.. there are a bunch more.. but thats where you start at..

the computer has a ground connection to the firewall..

there is a braided ground strap from the back of the engine to the firewall.. both of those need to be cleaned, wire brushed and reinstalled..

the braided strap usually goes on a green stud near the evaporator box..

transmission codes are in the p0700 to p0799 range and also above p1000..

but post any and all codes.. you may have to reset the scan tool to examine the transmission data stream instead of the engine data stream...

[GPster]

I think I found a third reason so maybe it fixed itself. Have not had any problems like initially described. Had the occasion to drive the same road yesterday and had the dog with me again. About halfway on the trip I noticed the O/D light flashing again. It was off at the start of the trip so something in the drive must have kicked it off (on). I was traveling along a state highway with a 55mph speed limit but because there are numerous 45mph stretches along the way I just set the cruise control at the lower limit. I don't mind driving the road at 45mph because it's only a two lane road with double yellow lines. The road also is also a path to the area mall and the most traveled road in WVa  so I keep in mind any build-up of traffic behind me. If/when that may happen I just hit the gas and speed up past the cruise control set point. That is evidently what kicked on the light. At my destination I tuned the ignition off and when I re-started the light had cleared. On the trip home I didn't use the cruise control and I didn't have any more flashing light. Must have been me trying to be smarter than the cruise control. GPster