02 Ford Explorer Sport Trac O/D light flashing

Looking for help with a flashing o/d light.

I have a 02 Ford Explorer Sport Trac. V6 4.0L with a 5R55E transmission. About 210,000 miles.

A few weeks ago after a trip i discovered i had a coolant leak. It took me a couple of days to figure out that it was the lower thermostat housing. Fixed that and I thought my troubles were over. WRONG.

A few days later the O/D light started flashing and I got to enjoy the wonderful “Limp Mode”. The problem only showed up when I had to slow down for a stop. As soon as I started to go again and it went to shift into second (or overdrive 1st) the o/d would start flashing and hello “limp mode”.

I got on the web and started reading. I ended up replacing the speed sensor (in the rear differential), the crankshaft sensor, and readjusted the bands with no luck. I would have to shut the truck off at every stop sign/red light just to avoid “limp mode”.

Last week I went to a friends shop to have them change the oil and we started talking about the problem. I got him to flush the transmission fluid and look at the codes.

He got the following codes: P0731, P0732, P0733, and P0734. Incorrect gear ration 1 - 4. He cleared them and nothing popped back up.

That cleared up most of the problems.

Same scenario as before but only after I reach 40-50 mph. If I’m just in city traffic it doesn’t pop up. And if I’m driving around with no stop signs/red lights it won’t reappear. But if i get up to 40-50 mph and have to complete stop, as soon as I take off again and it shifts into that second gear (or sometimes 3rd gear) it will go into “limp mode”.

I got a kid on the way and money is tight so it will be a few weeks before i can let my buddy dig into to it. After doing some more reading I’m beginning to think one of the solenoids is acting up, but I wanted to put it out to the community first.

So any thoughts or suggestions.

Your blinking OD light is Ford’s warning light for a transmission and drive line fault. Similar to a CEL but for the transmission instead of the motor emissions. Your fixes so far haven’t found and dealt with the core problem, so you have to dig deeper. Perhaps it is an internal problem, ie a shift solenoid.

Those codes are typical if the clutches are slipping. Improper solenoid operation is another code. Clutch slippage occurs due to wear or low fluid pressure. I fear the underlying problem will be internal.

update: so today while driving around i discovered that if i let off the gas during that first or second shift it won’t go into limp mode

With that knowledge, I think the problem may be line pressure. This can be checked by a competent transmission shop without removing the transmission. There are test ports on the transmission case that can be used to check the line pressure for various functions of the transmission as it works. It is possible that a solution may be found without a rebuild.

Update: So last December the transmission died out. We pulled it and found the Torque converter to have locked up and seized, but not before blowing metal all throughout the rest of the transmission.
Went to LKQ and got a transmission pulled from a newer model with less mileage. Back up and running now.

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