E4(uh-oh)D - troubleshooting manual operation?

[david85]

Hm...
There's something else here that we're missing.


But... If both shift solenoids being off produce 2nd gear(in drive), then they are

Awesome, thanks.
I've found several pages that say it should work, and others that say it should only have 2nd, so it's good to get some corroboration.

I'll check fluid level, and I also wonder if it's not something like the fact that the EPC solenoid is disconnected, so perhaps it's giving minimum pressure, not enough to shift? Or too much, which is keeping it in 2nd(both solenoids engaged)?

The shift linkage alignment... even if it were off, I should still "feel" the gear position no matter what the selector says. And I definitely have P, R,N,D,2,1 available as nice, clunky positions...

The EPC uses an inverse control strategy to make it fail-safe. In other words, maximum electrical signal will mean minimum line pressure. That way, a complete electrical failure will result in maximum line pressure. Same fail-safe strategy like on the older C6; lose vacuum signal, and the transmission thinks its always at WOT. This is in contrast to the mechanical AOD in the half-ton trucks that will go to minimum line pressure if the throttle valve cable ever snaps.

I don't know how many miles that shift linkage has on it, but I know my 86 can feel a bit vague at times. Having said that, mine isn't really fussy about precision when it comes to getting it perfectly in the right spot. If your other gears line up where they should be, then this isn't the problem.

As for both solenoids being off...ok, bear with me.

That is where you should produce 4th gear.
2nd gear is hydraulically forced by the shift linkage changing position, regardless of what the solenoids are commanding. And even though having both shift solenoids being off is still a valid shift command, it still gets ignored.

This is just the way ford engineered it back in the day. In reality, the E4OD is the evolutionary link between mechanical and electronic automatics, so the mechanical valve body still has a lot of direct control over what happens, and when. I even tested this on mine unintentionally years back when I incorrectly wired up my MLPS. Even when the controller was trying to electronically command 3rd gear (verified via live monitoring), the transmission would stay in 2nd so long as I had the shifter there.

 

[Thewespaul]

I learned something today