PCM Code

[X JBM X]

Ugh. Took the PCM out of the truck, and read the code. Order form sent in!!

[hayjayhorses]

did you get your chip yet?

[X JBM X]

Yep, got the chip and installed it yesterday before my 300 mile road trip.

The power is amazing!

The shifting under heavier throttle is awesome, but under light throttle not so much. It seems to be "over-clutching" - if you think about it like a manual, in between gears, if you give the truck too much throttle and then let the clutch out it does that forward buck before slowing down to catch up with itself.

I'm assuming that's not normal, but could someone please confirm that? It happens in both 80dd and 120r.

[cleatus12r]

Which shift does it occur in?

I know your order form said that there weren't any transmission modifications but are you sure? Could a previous owner have done something to it?

The tunes you have are very similar to all of the PMT1 tunes that Bill has put out for quite a few months (and it's the most-used 7.3L platform we sell). I have looked at the programs and can find nothing askew with them.

Which shift (1-2, 2-3, 3TCC apply, or 3-4)? I'm wondering if you are feeling the 3rd gear torque converter clutch apply at approximately 35 MPH. Your NVK2 didn't do that under normal driving.

[X JBM X]

Originally Posted by cleatus12r

Which shift does it occur in?

I know your order form said that there weren't any transmission modifications but are you sure? Could a previous owner have done something to it?

The tunes you have are very similar to all of the PMT1 tunes that Bill has put out for quite a few months (and it's the most-used 7.3L platform we sell). I have looked at the programs and can find nothing askew with them.

Which shift (1-2, 2-3, 3TCC apply, or 3-4)? I'm wondering if you are feeling the 3rd gear torque converter clutch apply at approximately 35 MPH. Your NVK2 didn't do that under normal driving.

It is most certainly the 3TCC, and somewhat in the 3-4. Is this normal?

[cleatus12r]

The most ridiculous thing about Ford programming is their TCC apply strategies. The 95-97 guys really have it bad because the torque converter clutch apply system consists of an on/off solenoid and valve and a ridiculously long delay between the 3-4 shift. It basically goes from 3rd lock to 4th unlock and back to relocking the torque converter clutch. It does this in a 1.5-2 second window so us guys get a really long, drawn-out shift (seemingly).

The PMT1 strategy that you have in your Super Duty does the same thing...but over a much shorter time. The torque converter clutch is commanded off during the 3-4 shift but it is over a much shorter time and then the fluid pressure is ramped back up (instead of just being turned on) over a time of a few milliseconds. This gives the feel that there really isn't a loss of TCC apply but it IS there.


Without feeling the shifts or being able to scan data during the shifts, it's hard to know what is actually going on. I'm going to say that your torque converter system is likely a bit more responsive than most to fluid pressure changes. Unfortunately, I cannot say for sure.

[X JBM X]

I'm not quite sure what that means...

In other words, am I going to toast my tranny using this chip, or should I be good to go? I mean, I LOVE the extra power that I'm getting, and the shifts feel great when I'm on the throttle, but when cruising around town at ~35mph when the TCC kicks in, and it does that jerking thing, I don't wanna burn up the trans.

Since I didn't go back to read if I already posted it, I'll try to describe the feeling.

It's like if you're in a manual trans car, and you go to switch gears, push in the clutch, shift, and then hit the gas a little bit before releasing the clutch (almost like you let the clutch out a little too fast when not racing and just dumping it) making the car forward buck a little before slowing down the RPM's to properly engage the gear.