4L60E Transmission Torque Reduction during WOT

[recrit]

Is there any reason why the torque reduction would not work during a WOT shift?
My logs show that it's correctly pulling the timing during a 1 to 2 shift during a part throttle shift. During a WOT shift, no timing is pulled.


PCM: GM LS1B
OS installed: EFI Live Custom 04110003
Torque Reduction Upshift tables: D0801, DO802, D0803

[recrit]

I added a desired shift time of 0.2sec for the 1st to 2nd shift and now the transmission torque reduction is working at WOT. The shift time was 0 previously when it was only working at part throttle.
Does the desired shift time need to be > 0 for the transmission torque reduction to be used during WOT?

[joecar]

Thanks for posting.

[joecar]

Moved to 4L60E section.

[joecar]

I have seen TR not work at WOT, but I never realized this happens when desired shift times are zero.

Yes, I would set the desired shift times to 0.1s-0.2s.

A few quick questions:
- which PCM do you have (part number),
- which year/model/vehicle is the PCM,
- which year/model/vehicle do you have,
- what is the base OS id.

I want to see which PCM's and OS's show this behavior.

Thanks
:cheers:

[recrit]

I'm going to set it back to 0 sec to confirm that this issue occurs again. I'll post the results.

- PCM: GM LS1B: Service 12586243, HW 12583659, other numbers: 12587670, YFXJ. However, this is not the original stock PCM. The original got bricked so I got this one off of eBay with the same service #12586243.
- year/model/vehicle: 2004 GTO
- Base OS: 12587604

Transmission: 4L60E PerformaBuilt with their custom shift kit

[recrit]

CONFIRMED.
Test: 1-2 shift time set to 0 sec.
Results:
- Part throttle: pulls the correct timing during the shift for the TR% set in the tune.
- WOT: does NOT pull any timing during the shift.

[joecar]

recrit,

Thanks for the confirmation.

Also try this (if you have the time):
set the shift times to 0.001s and 0.01s and see if TR at WOT works properly in each case.

Then, for normal running, set them to 0.2s (this is a quick shift, and TR sufficiently protects the trans).

[In-Tech]

I'm not so sure you want the shift times at 0, the early stuff may not care but when the adaptives start doing their stuff in the later controllers, it very easily kills the trans :(

[joecar]

You may want zero shift times when you have a shift kit installed.

[recrit]

joecar - that's exactly how i got to this point. I read everywhere that you should set the times to 0 when you have a shift kit and then use TR to soften the shifts - which was not working.

I should have some time later this week to test 0.001s and 0.01s.

[recrit]

joecar - Below is a summary of all the tests that I've run.



Tune Entered: Desired Shift Time (s)
After Save/ Re-open: Desired Shift Time (s)
Shift Tested
Torque Reduction Work?
Notes


0
0
1-2
NO
tested multiple times, all had no TR


0
0
2-3
NO



0.001
0
1-2
YES
TR worked even though the tune showed 0 sec after saving and re-opening


0.01
0.0125
2-3
YES



0.1
0.1
1-2
YES



0.2
0.2
1-2
YES



0.2
0.2
2-3
YES



0.6
0.6
1-2
YES

[joecar]

recrit, Thanks, appreciated :cheers:


The Save/Reopen values you see are due to the fixed point binary representation not being able to represent all fractions (so 0.0.125 is the closest value that 0.01 can be represented as).

The 0.001 -> 0 that you see is not a zero, you need to increase the display precision and you will see that is is something like 0.000125.

[recrit]

joecar, that makes sense now for the "Save/Reopen values".
I set all shifts to 0.2s now and everything is working as expected now. Thanks again!