T42 TCM tap shifts

[GraphiteSRT]

Were their any vehicles with the 4 speed T42 TCM that had the tap shift control.


I have an 05 GTO A4 and it seems to be only lacking this feature

Their are tables in the TCM that have these functions

[gmtech16450yz]

05-07 Pontiac Gran Prix GXP used tap shift on a T42/ A4. I looked at the wiring diagrams and it looks like it's possible. Terminal 10 is the tap shift input to the TCM. I looked at the GMT900 truck shifter for the A6 (also has tap shift) and it looks like it's wired similar to the GXP, except the signal goes into the BCM not the TCM.

I'm thinking at least in the trucks, (didn't look at the GTO diagrams) you could put the A6 shifter in it and wire the signal directly to the TCM on pin 10. I'm thinking even though the tables are in there (the tap up/tap down tables are also in my trucks T42 calibrations even though it doesn't use it), you'd probably need a different OS to make it work?

I think someone needs to try it. If it's as simple as running one signal wire from the buttons on an A6 shifter to the TCM that would be an easy upgrade to tap shift. I'd be buying a shifter with the tap shift buttons next week if I knew it would work! Not sure how you'd tell it to go into manual mode though so you could use the tap shifter inputs?

[GraphiteSRT]

instead of using another shifter, i would like to wire buttons on the back of the steering wheel.

I am wondering how the tap switch works, it may just be a positive or negative pulse depending on which way you tap it.