TCC Tuning! TCC Lock 3rd at WOT?

[darcy]

Mark,

My interpretation of the tune as is:

- Taz set you up so that it will still unlock at WOT. Try setting D1008 to 100% for all cells.
- D1002 & D1005 are controlling converter lock - D1002 won't lock it until 76MPH @ 100% throttle, D1005 is requesting an unlock if you go 100% TPS while slower than 70MPH

[EagleMark]

Thanks darcy! I think you got it, matches up perfect to logs I got earlier.

Will adjust and test tomorrow.

[Taz]

Hi Mark,

Sorry the D1008 trick didn't work - have never tried that before. Was looking for a quick and easy way to arrive at your needs.

As Darcy pointed out, a rework of D1002 and D1005 should get you there.

As an aside, for heavy towing with a generally stock 4L60, the gear selector should be in third (not OD) for the trans to survive. When I flash a towing tune, I setup Tow / Haul mode to keep the TC locked in third gear.

Now that you are using an 0411 PCM, you can wire a momentary switch to access Tow / Haul mode. This would give you access to two shift patterns on your 1998 Vortec truck.


Cheers,
Taz

[EagleMark]

It's all good Taz! As always appreciate the help.

Sometimes you just go blind looking at stuff and need a fresh set of eyes... the melding of the minds is always good too!

WOT 3rd gear TCC Lock Up issue fixed! Woo Hoo!

[EagleMark]

I thought I was happy with trans tune before making all these further adjustments. Man was I wrong, this is way better. It's not a race car at all so never really noticed the 3rd gear WOT and TCC coming on, but that is fixed now too!

Overall it's just sweet, nothing hard or harsh at light throttle, half throttle and the shifts are firmer. WOT 1>2 shit I can chirp a tire!

TCC lock up times are about half what they used to be, can feel it nice and no bang.

Main goals of this thread and questions are to reduce wear from slipping and decrease heat from slipping. Without causing undue stress or wear on tranny. To produce a good tranny tune for feel and drive ability of vehicles, along with increased trans life and less heat.

From earlier in thread:

TCC PWM Duty Cycle D2903 min and D2904 max. I've read a few times to decrease wear and heat that the max should be 99-100 % and min should be lower but only a little bit. Basically keeping full duty cycle to avoid slip.

Did a log with stock setting which max was basically 98% and the mins were as low as 10% up to 21%. During Lock Up there was no slip, well 1-2 RPM and duty cycle would change to low numbers like 40%. Even when hard acceleration there was no slip, eventually the TCC was unlocked where it should have by TPS% setting.

Increased the min to be 96% with max at 98% and still no slip but duty cycle did stay high. Is this even needed then? Is this causing an undue strain? Data logs show the TCC Duty PID GM.TCCDC at max of 98% long before TCC is Applied, when locked goes much lower.

This is my first time adjusting these settings and I see no results?

Please explain?

[slows10]

Good thread, thanks for sharing good info. Going to start "adjusting" a 4l70e shortly

[hog]

Abobout 10 years ago I got an L31 calibration that disabled the 3rd gear WOT TCC apply and it was worth about a tenth in teh 1/4 mile. The trans would shift into 3rd gear, then lock the TCC at 75mph(as per the stock cal) and cause some serious bogging in acceleration.
4l80e cals lock at WOT in 2nd gear, the 60e's lock in 3rd at 75-85mph, all stock of course.

peace
Hog

[EagleMark]

A tenth in 1/4 mile does not sound like a lot, it all helps of course. But acceleration in 3rd WOT without TCC locking up is a huge gain in acceleration looking at MPH going up!

[joecar]

It's all good Taz! As always appreciate the help.

Sometimes you just go blind looking at stuff and need a fresh set of eyes... the melding of the minds is always good too!

WOT 3rd gear TCC Lock Up issue fixed! Woo Hoo!

Hi EM, what did you do...?

[joecar]

TCC lock/unlock is a combination of PT apply/release tables and throttle release table...

when you graph them on common axes (the throttle table has to be rotated 90 degrees), you should get a hysteresis band between the PT apply and release tables, and the throttle release table should avoid overlapping into this hysteresis band.