TCC release help?

[horsehaulin]

Going through the Appalachian mountains has my 5.3 Envoy downshifting quite often, I'd like to restrict the downshift to a TCC release only if possible. Anyone out there know how to keep this transmission in fourth and unlock the torque converter so it will help save mileage. I know GMs used to do this years ago and it seems they took the easy way out and left that tuning out.

[horsehaulin]

21133

[ScarabEpic22]

First thing to do without even looking at the tune is to use SSpddemon's A4 Trans worksheet (it's stickied) and make sure all the up/downshifts are configured per his logic. It makes the transmission not "think" or wait between TCC unlocks or downshifts, just operates smoother IMO. Then you can use it to overlay the 4th TCC lockup curve with the 4->3 downshift and configure to your liking.

[joecar]

Lower (and shift right) the 4->3 shift curve to hold off the downshift.

~ posted by phone ~

[horsehaulin]

I'm not particularly looking to hold off the shift as much as I'm looking for the Torque Converter to release rather than a full gear kick down. Does that make sense and would it save fuel in the long run or will I just end up chasing my tail?

[joecar]

You want the 4th gear TCC release to occur before the 4->3 downshift...

so you have to position the 4th gear TCC release curve above the 4->3 downshift curve (and make sure they do not cross)...

then you fine tune by doing this:
- move the 4th gear TCC release curve up/left (to make this event happen sooner)
- move the 4->3 downshift curve down/right (to make this event happen later)

( while doing this you must make sure that the 4th gear TCC release curve does not go above the 4th gear TCC apply curve... be careful, yours are very close to each other )


As Erik said, use the spreadsheet to space out the curves and make sure that none of them cross any others.