trxmxzx

iTrader: (7)

I know cammed 6.0 and stock 60e is a short lived life.

Recently I was working on a buddy's Tahoe with this current setup, and trans is starting to let go going into 2-3 shift

I noticed in the tune file that gm setup 3-4 shift time to 0.0 across the board

2-3 was like .5 or .6
1-2 was about the same

a trans guy has told me you need to leave some room of time for allowing shift soo .2 say

now I woke this morning wondering is the desired shift time allowed for trans to shift or for the computer to release its full power (torque management timing between shifts)?!?

Vortec350ss

iTrader: (20)

I think youre on the right track with half a second. You can go quicker if you want to really turn things up. I think at one point I had mine at .2 or so.

Last Call

iTrader: (4)

The desired shift time allows the PCM to adjust pressure to achieve a shift time. I don't think the trans is capable of shifting faster than .2-.3, so that is probably a good number to use. If the trans is starting to let go, I would lower the shift time, increase the pressure, and increase the torque management at higher torque values. The will allow the transmission to shift as quickly as possible and reduce the load at the shift.

If you zero out the shift times, there will be no trans adapts.

trxmxzx

iTrader: (7)

thanks thats what I was looking to hear- just trying to nurse this thing along to by me time to get my trans out- (I'm going 80e- he's buying my built unit)

i did adjust just to a shorter time and it seemed to make it worse- I took and copied the "performance" line pressure for the 2-3 shift

01ssreda4

iTrader: (87)

I run em anywhere from .0 to .2. Any higher and you get the computer jacking with the shifts and in my opinion it will take pressure/feel away from how you have it set.

smokeshow

iTrader: (16)

Desired shift time just provides a target for adaptive shift learning. Things like environmental conditions and transmission mileage/fluid age impact how quick the trans makes a gear shift, so the PCM uses closed loop control to always attain the same shift time over the life of the transmission. Setting the shift times to zero disables the adaptive system and results in a shift that occurs just as fast as your shift pressure settings will allow. I prefer to keep it enabled seeing as there's no good way to measure clutch apply time vs pressure with aftermarket software like HPT. Just give it a small value like 0.200 or less and let it do its thing. If you set shift time low and its not happening that fast, then you've reached the limits of how fast a drum can fill with fluid.

trxmxzx

iTrader: (7)

thanks for explaining this, I ended up putting it at .3 then .2 which really showed no difference

just was curious on how the whole system works with each other

01ssreda4

iTrader: (87)

It takes time for the adaptive to work. Meaning when i first tuned mine shifts were firm, then they tailored off in feel over time. When I reflashed the PCM (and presumably adapts were reset) shifts got firm again with no trans calibration changes. You wont feel the adaptive immediately is my point.