Keeping the TCC locked up in tow/haul (truck)

[larboc1]

I'm pretty disappointed in the way the torque converter behaves in either normal or performance (tow/haul) mode.
I don't care about the NVH issues, especially while towing, of keeping it locked up.
1) locks up very softly, how do I/is it ok to quicken it up?
2) Is it ok to keep the TC locked during shifts both up and down?
3) How do I get DFCO to actually work? I've tried raising the rpm limits for entry, but it seems like the MAP values don't get low enough to set it into DFCO while letting off the throttle down hills (30-35 kpa). Is the IAC throttle follower letting too much air by?

I've only had hp tuners for a couple weeks so I'm making changes slowly, but I've been working on getting the normal shifting much more like I want it to, starting by copying a 1/2 ton 5.3 strategy and changing it.

2001 2500 4wd truck 3.73's lq4

[gman4dx266]

1) locks up very softly, how do I/is it ok to quicken it up?
2) Is it ok to keep the TC locked during shifts both up and down?
3) How do I get DFCO to actually work? I've tried raising the rpm limits for entry, but it seems like the MAP values don't get low enough to set it into DFCO while letting off the throttle down hills (30-35 kpa). Is the IAC throttle follower letting too much air by?

1) set your minimum duty cycle tcc table to 90 and the max table to 100. It will feel like a 5th gear shift. (like a 4>5)

2) Do not do this. Expect a boom sooner or later if you do. It's like shifting a manual without using the clutch. You can try it if you're feeling up to it... it's very rough feeling; imagine the inside of the trans.

3) Someone else will have to chime in on this, not a big DFCO expert.

[larboc1]

1) sounds good, I'll try that.
2) The only reason I ask is that I see diesel pulling trucks doing just that, using a switch to keep the tcc locked up during shifts.

[larboc1]

The max tcc duty cycle is 99 across the board, do I leave it at this or change to 100? why is it 99?

[decipha]

how does the tcc locked could cause any transmission damage? if the converter is over its stall speed its locked anyway, it seems as though the effects would be minimal as rpm is increased

this is of concern to me as i have some vehicles i tuned remain locked during shifts due to high stalls being used as daily drivers (IE 4000+ stalls)

more info please... subscribed

[01ssreda4]

No at over stall speed its not locked. It still slips. It cushions the shifts from the engine side that's applying power. You do not lock your converter during a shift.