Mach2
January 1st, 2017, 08:36 AM
I am not new to tuning or to EFI Live but I cannot figure out how to tune this trans in a 2016 Colorado. In drive it shifts 1-2 between 6200-6400 RPM, in tow/haul mode it always shifts at 6800 RPM. In addition in tow/haul mode the trans will not go into 6th gear. In looking at the tables I assume drive = Normal shift pattern and tow/haul = Pattern A (Pattern B is disabled). My goals for the tune are:
1) Raise 1-2 shift point in normal pattern to 6800 rpm
2) Raise part throttle upshift points (TPS < 25%) so engine is not lugging at 1000 rpm
3) If possible shorten and firm up shifts a bit
I have gone through all the trans tables and cannot find where they are actually controlling the 1-2 shift at WOT. In the Normal or Pattern A Part Throttle Shift tables the 1-2 shift is supposed to occur at 34 MPH for both patterns but in reality they occur at 39 and 43 MPH. The Normal and Pattern A WOT Shift Speeds has a 1-2 shift at 30 and 40 MPH respectively. WOT Shift RPM for both normal and Pattern A is set to 6800 rpm. So if the WOT Shift RPM table allows shifts at 6800, and the WOT and Part Throttle Shift tables show values below actuals, what is controlling the shift? If I can get this figured out I will know which table to changes for the part throttle upshifts (below 30% TPS).
I have heard that this trans is not as easy to tune as the 4L60 I am used to (decrease shift times by 0.1 seconds and increase line pressures by 10%). Any advice on how to shorten shift times and firm them up a bit.
Any advice would be appreciated. Stock TCM tune file is attached.
1) Raise 1-2 shift point in normal pattern to 6800 rpm
2) Raise part throttle upshift points (TPS < 25%) so engine is not lugging at 1000 rpm
3) If possible shorten and firm up shifts a bit
I have gone through all the trans tables and cannot find where they are actually controlling the 1-2 shift at WOT. In the Normal or Pattern A Part Throttle Shift tables the 1-2 shift is supposed to occur at 34 MPH for both patterns but in reality they occur at 39 and 43 MPH. The Normal and Pattern A WOT Shift Speeds has a 1-2 shift at 30 and 40 MPH respectively. WOT Shift RPM for both normal and Pattern A is set to 6800 rpm. So if the WOT Shift RPM table allows shifts at 6800, and the WOT and Part Throttle Shift tables show values below actuals, what is controlling the shift? If I can get this figured out I will know which table to changes for the part throttle upshifts (below 30% TPS).
I have heard that this trans is not as easy to tune as the 4L60 I am used to (decrease shift times by 0.1 seconds and increase line pressures by 10%). Any advice on how to shorten shift times and firm them up a bit.
Any advice would be appreciated. Stock TCM tune file is attached.