1-2 Shift neck snapper

[Lakegoat]

05 GTO with built 4L80E.
My 1--2 shift is HARD. I have tried modifying the shift time table, no help. I went to Trans--Auto shift properties--Shift pressure--upshift--Pattern X--1-2 shift. I zeroed out the table up to and including the 415# box. Wrote the tune, and my car would barely run. I started it about 10 times,same thing--starts and dies. So I changed it back to the original numbers, everything is ok. I went to Shift Pressure Modifier, 1--2 shift and added negative 5 thru 10 in the center boxes. Same thing again, car will not stay running.
This is my street tune that I am working on. The hard shifting is OK at the drags, I don't notice it and I keep a separate tune. I would just like it a little easier on the street. It is only the 1--2 shift. 2--3 and 3--4 are fine.
This is a 4L80 running on a 4L60 tune with the relays.
Thanks
David

[Ranger6202]

i see you have .475 in there for your shift time, generally that would be way slow, but in your case have you taken it any greater than that value?

[Lakegoat]

i see you have .475 in there for your shift time, generally that would be way slow, but in your case have you taken it any greater than that value?

I haven't tried a larger number. My drag tune is .125 and there is no difference from that to the .475 (that I can tell) so I didn't stretch it any further. I will give it a .700 and see what that does.
It has a modified shift kit and some oil passages modified so it may not be possible to soften it. The builder is not a tuner so he really can't help.
I was really wondering why the shift pressure changes affected my engine.
Thanks, I'll report the .700 change.
David

[Lakegoat]

I tried .700 on the 1--2 shift and it did not do much. Changed the shift time to .900 and it seemed a little smoother. I changed my shift pressure from 92.8 to 90.1 and that seemed better, but my idle went to crap ???? Wants to idle about 1000 instead of 850 and in gear it wants to idle at 1200 or 30mph. Crap!
I changed it back to 92.8 and the idle went back to normal. Can anybody tell me why the trans shift pressure would change the idle?
Thanks,
David