4L80E Will NOT SHIFT WOT

[Mike@Vengeance]

Guys can anybody take a look at this tune and see why this car will not shift under WOT to 3

The 1-2 shift happens as commanded.

The 2-3 shift at WOT just will not occur. I have tried all kinds of stuff and no luck.

The 2-3 shift is set at 70MPH and 6000 RPMS and car will go 100MPH in 2nd gear so the speed makes it no problem and so should the RPMS.

Any help would be great.

4L80E not shift 8th burn_0000.tun

[Taz]

Hello Mike,

Somewhere between the 4L80 segment swap, and COS upgrade, it looks like some of the transmission up / down speeds got a little muddled.

Try the attached tune - hopefully it helps get you going - such that you can fine tune to your own preferences.


Regards,
Taz

[ls1mike]

I had similar trouble with an incorrectly configured transmission output speed. I'd play with that as the speedo may be correct but the trans may not be.

[slow67]

I had similar trouble with an incorrectly configured transmission output speed. I'd play with that as the speedo may be correct but the trans may not be.

X2. The scanner speedo isn't what the transmission goes by.