M5OD-R1 swap, new top cover missing neutral safety switch | Ford Explorer Forums - Serious Explorations

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M5OD-R1 swap, new top cover missing neutral safety switch


New Member
June 20, 2010
Reaction score
City, State
Seattle, WA
Year, Model & Trim Level
1990 XLT
I swapped my destroyed original M5OD-R1 transmission (1993 Explorer XLT 4WD) for the same from a 1996 Explorer. Everything initially looked identical...

Except the top covers are different. The new '96 top cover is lacking a sensor, which research is telling me is the neutral safety switch. I have not yet retrieved error codes (I'm at work), but after driving for ~ 20 minutes the check engine light came on.

So regardless of the light, will leaving the plug for the switch disconnected (again, nothing to connect it to anymore) cause any issues? I would prefer NOT to use the old top cover, as it got pretty badly browned when the tranny melted its insides.

And lastly, if it does turn out to be the cause of the CEL, would shorting the wires trick it into thinking everything's ok?

I put a m5od with the newer top cover like your in my 91 and just spliced the 2 wires together on the harness. Never had a check engine light or anything of that nature since I done it about a year ago.

Have you tried to pull the check engine light codes to see why the lights on?

Pulled the codes in the parking lot, got home and looked 'em up just now. 539 and 176. Unrelated to the transmission. (Lean mix. Probably because the car has been sitting with that gas for about 9 months.)

I'll probably leave it alone for now unless a new code comes up. Thanks for the info, I'm much less concerned.

bypass neutral safe switch

What color are the wires going to the neutral safe switch? I need to do the same thing to mine and don't want to short anything out.