[wizkid1358]

Tuning the truck in my signature. What controls the amount of TCC duty cycle during shifts on a 4r100? On the 2-3 shift it slips a little too much and on the 3-4 it doesn't slip enough making for a harsh shift. Has a Circle D converter that seems to be finicky on lockup rates. Blue line is TCC duty cycle or BCSDC_OUT. Orange line is TCC slip or SLIP_ABS.

converter slip during shifts.jpg (44.6 KiB) Viewed 854 times

[Blklightning01]

Question, what are you using to tune with?
Do you not have PID's for full transmission control? I remove all torque management from my tunes, but I have extra clutches in all drums and overdrive clutches as well, Transgo Tugger kit, pressure boost valve and some internal pump mods. Shift pressures and mph shift points are tuned via BE and strategies from Core Tuning. If you turn off torque management, you will have set pressures via the tune.
This looks like torque management control. Since strategies differ in the "FNxxxx" numbering system, I never relay on that type of information and actually open the pids to determine what they are specially for. Some strategies have much better descriptions associated with the PID then others.

[wizkid1358]

I'm using BE to tune also. The problem is not the shifts themselves. The orange line is converter slip. It's the engine RPM minus the input shaft RPM. You can see the TCC duty cycle is different between those shifts and I'm trying to figure out what controls that duty cycle during the different shifts.

[Blklightning01]

I installed this Transgo 4R100 LU, which eliminates PWM of the converter lock up. Mine is locked or unlocked, "no" slip per se. I also use only billet triple disc lockup clutch converters. So, now its a matter of is there a PID in your strategy that controls the Pulse Width Modulation?
Let me pull up a tune and see if I have the pid or not.

[Blklightning01]

I just had a thought, are you adjusting the converter mph lock up points in the tune? interesting read at https://www.fullsizebronco.com/threads/ ... od.204165/

[Blklightning01]

Open up Trans-TCctl settings in your tune. i changed the Throttle progression settings as well. Suggest comparing a stk tune to the tune you are working on and increase the numbers and try it. I found the best to learn is make a change and see if it does what you want or not. I have my diesel truck lock ups different than my turbo sbf in a F150 due to difference in engine torque output. I also, do not lock the converter in the turbo F150 till 3rd gear at low tps readings, unless in boost at TPS voltages above 3.5v in second gear. My stall is 2400 in that truck. Diesel has a "low stall" converter, similar to a 6.0 PSD, but some internal tweaks to the stator. I also don't allow a 1st to 2nd gear shift at higher tps reading to deal with wheel speed/spin.

[wizkid1358]

I don't see anything in TC CTRL settings that would help this issue. I have changed the throttle progression settings but that just changes when the converter unlocks based on throttle change rate. That article talks about the torque table for converter/trans control. I was thinking that could be the problem. The torque calculation is typically higher on the 3-4 shift than the 2-3 shift at low throttle positions. I will have to play around with the torque calculations. Yes, I have changed lockup/unluck points in the tune.

tc ctrl settings.png (131.83 KiB) Viewed 756 times

[Blklightning01]

Within your screenshot I see 5 potential pids that may help you tune exactly what you want to do. Since I remove all PWM factors from TC lockup/slip and use actual psi in relationship to TPS to control shift "feel" I have no need to tune those pids.
Also, I want no slippage during gear changes, that adds wear and heat. Just my preference in how I do/like things to work.
Honestly, I would at least try making chanqges and log for the actual change that took place or not. You can always change the pid back and if you test the changes at tps readings below 2.4, it won't hurt the trans. You might see lower operating temperatures as well, as you know high atf temps are what kills the trans outside of part failure.

[wizkid1358]

double posted on accident.

[wizkid1358]

I can confidently say the min/max shift times before lock, throttle progression, max rel TP for closed throttle unlock, max TP relative for unlock with brake, and time to stay unlocked after brake is pressed do not affect the amount of slip during shifts. The clutch gain affects all shifts equally. I have played around with them already. Torque Conv Duty Cyle Lock Up just controls the duty cycle of the TCC when SW to Enable TCC Lock is enabled. I am not interested in an on/off converter. I have had vehicles with this and have friend's vehicles I still ride in with this. This vehicle will be remaining PWM. I also don't have a problem with heat even when towing. I have 3 trans coolers on it and 2 of them are on a 185 degree thermostat that hasn't even had to open yet. I am just trying to get a little more TCC duty cycle during the 2-3 shift and a little less during the 3-4 shift.