[SpeedR]

Originally Posted by L8Apex

I have the same 4.88 FD setup as PantsDants in my AT6 (actually followed his instructions to duplicate everything, much thanks!!) and I'm loving it. I'm also curious if the tune can be optimized for the higher final drive.

From what I can see the AT has a speed sensor on the trans output shaft in addition to obtaining the VSS (vehicle speed sensor) signal from wheel sensors. My theory is it uses the speed sensor on the trans to shift the AT at correct shift points, and wheel speed sensors for dash cluster speedo and stability control stuff. The separate speed sensors allow shift logic, speedo, and VSC to all function accurately in spite of the FD change.

Gear indicator on the AT comes from the TCM which uses the trans-mounted speed sensor so it should be unaffected by FD changes on the AT6. But current gear is calculated in the MT6, probably from wheel sensors, and might require an ECU change to fix this, not sure.

Engine tuning itself seems independent from gear ratios so I'm guessing there's no difference in actual tune, but I'm hoping someone can confirm. (Shiv?) I'm not familiar enough with the tables yet.

Thanks for the info.
Can any one confirm this?