4R70W Transmission issues with '96 Ford Explorer | Ford Explorer Forums - Serious Explorations

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4R70W Transmission issues with '96 Ford Explorer


Well-Known Member
November 30, 2011
Reaction score
City, State
Edgewater, FL
Year, Model & Trim Level
1996 Explorer 5.0
Hey Guys,
I'll start with this--everyone loves a badass picture of a beloved Ford Explorer, so here's mine:


I've been having some issues lately with my transmission on my 1996 5.0L Explorer.

My Explorer is a '96, but when I did my 2WD -> 4WD SAS swap, I installed a 1998 Explorer 4WD transmission. This required re-pinning of the transmission harness, per the diagrams below:



I'll note that the truck has run great since I did the swap without these issues, so it is not related to the pin-swap.

I initially noticed an issue when taking off from a stop--it seems sluggish, then it catches up with itself and shifts fine through the gears until it is supposed to shift into overdrive; but it will not shift into overdrive. Pressing the O/D ON/OFF button does not do anything, nor does it light up the O/D ON/OFF light on the dash.

On occasion, I've caught the O/D light flashing, and it has 'bucked' when trying to shift into O/D when letting off the gas at speed, but neither are consistent.

I've pulled the codes from the CEL and initially I saw these:
(Mind you, it's been years since I ever pulled codes from this truck, but these ones were listed as CURRENT)..



The EGR/emissions codes don't concern me much right now and I don't consider them related to my transmission issues right now, so just disregard--

I'll note too that my speedometer stopped working about 1.5 years ago, which I've learned to live with and hasn't bothered me too much, but that vehicle speed is properly reported real-time on my OBDII reader, so the issue with that shouldn't be the VSS itself, rather most likely something behind my dash. I've replaced the VSS several times trying to diagnose this speedometer issue initially to no avail, so the VSS is relatively new.

Once I pulled these codes, I cleared them and continued to drive the truck for a short period to see which one(s) came back first. Here's what I got:


Though none of these were active.

I once again cleared those codes and drove around (all symptoms were still ongoing), re-pulled ETC's and found:


I repeated this several times to determine what codes were coming on first and coming on consistently.

The P0500 comes back, as both active and historic, but consistently. (Again, not worried about the active evap system ETC at this time).

If driven further distances, most of the remaining ETC's come back as well. For instance, these came back after just afew more driving miles, although after at least one engine start cycle too:


After clearing, another day of seeing ETC's, the first ones to pop up are:


I've included as much background information as I can to help y'all get a better understanding of what's exactly going on here, so thank you if you've stuck with me this far--
My question to you guys is this:
Do these codes, in conjunction with eachother, point to something specifically? A harness connector instead of individual component malfunctions? Can anyone here verify that all of these codes deal with the PCM, or a certain connector/harness that I should take a look at before I start replacing transmission solenoids?

Would a faulty internal transmission harness lead to these ETCs? Faulty PCM?

Any and all help you can provide would be great!


Have you considered that it may be some sort of torque converter failure, or the torque converter control circuit?

Have you considered that it may be some sort of torque converter failure, or the torque converter control circuit?
It's not impossible but IMO the symptoms do not seem consistent with a TC failure.
I did replace the torque converter within the last 7-8 years, as my original one did fail and caused trans fluid to leak consistently-- a symptom I don't have right now. (yes I've checked trans fluid as well, and it is topped off--). This was prior to my 2WD -> 4WD conversion, though I kept my new TC when I did the swap

Alright, so I dug into if further today..

Took the interior apart and got to the transmission harness through the access cover underneath the carpet to find the transmission harness connector wires. It looks like something started eating through the wire insulation and completely stripped all 7 wires going into the transmission connector, and likely caused all of the codes and problems I started experiencing.


I was able to re-use the pins and replaced the wires going into the connector and so far everything seems back to normal.

Bottom line is if you get ETC's that all correlate with functions related to the ones for this electrical connector, I would definitely check the wires!