Torque Converter Lock/Unlock

[gabeyd]

2000 Excursion 7.3 Diesel, PHP Phoenix 40T, 80FS, 80DD

I was under the impression that Bill used PMT1 shift strategies, but I'm seeing my torque converter unlock as soon as I touch the brake. It just makes no since to me, and is one thing I have always disliked about my stock PCM.

I let my foot off the throttle to slow down, the engine does some braking, but it isn't quite enough, so I put my foot on the brake. Now the TC unlocks, and so the engine is no longer helping me slow down, so I have to brake harder. If I let off the brake, the TC re-locks, and the engine slows down again. I hate this.

I thought PMT1 shifts kept the converter locked when decelerating, even if touching the brake petal, at least down to a certain speed...

Why isn't my PHP chip doing this, on every setting, even on the 40T setting (though I have not towed with it yet, this is all tested with just the truck).

Thanks.

[cleatus12r]

I'll let Bill know of your troubles. He doesn't use PMT1 on the Excursions because the PCM families are different between the trucks and the Excursions. If DJ (Soutthpaw) sees this, he may have some insight because he is using the PMT1 equivalent in his Ex.

[gabeyd]

Thanks. I think I had PMT1 shifting on my old chip for my Ex before I switched to PHP. So I know what I'm missing in shifting.

The engine is much smoother, and less smoke with the PHP, so I like my engine tuning better, but so far, I like my shifting (or really Torque Converter lock) less than on my old chip.

[Jackpine]

gabeyd - I drive a gasser, and have the same hangup you do on the way the Torque Converter functions.

I want everything to work more like a manual transmission! If I let off on the gas, I expect the engine to start slowing things down. If I push in on the clutch pedal, I want everything to "freewheel".

But, we don't have those inputs in the automatics, do we? Given the way things are designed, I doubt if we'll ever get what we want.

And, thinking about how things work, it's probably an impossible design criteria.

- Jack

[gabeyd]

Ya, I do with I had a manual, but they don't make them for the Excursion, and I'm not going to undertake a swap.

But my previous chip left the TC locked until you got below 30 or so, no matter what happened with the brake. It works better for me, especially when towing...

We'll see what Bill says.

[Sburn]

Interesting subject. Like Jack, I drive a gasser, so it's not always apples-to-apples with the diesel rigs.

But on the subject of T/C locking/unlocking, I was going though the transmission part of the factory service manual (2007 F150) one day. Ford's own transmission road test procedure suggests that the T/C should stay locked when letting off the gas above ~40MPH and unlocking only when the brakes are applied. But my truck has never done this, either when stock or w/ Gryphon. Letting off the gas unlocks the T/C, brakes or not.

From what I've read here and other places, it doesn't sound like anybody's 2004+ F150 stays locked when tipping out of the gas. So who knows what Ford was thinking...