Why is my new tranny and TC shifting so late?

[V-10_Killer]

I just got a new FLP tranny in my car with a new TCI 3800 stall converter. But it shifts WAY past where I want it to and I don't know why. It's not slipping between gears, and shifts firm when it does. But, for example, my setpoints are 1->2 shift at 37mph & 6000 rpms. But it shifts at 42mph & 6700rpms. 2->3 shift is set at 73mph & 6000 rpms, but shifts at 78mph & 6800rpms. BIG DIFFERENCE. Why? The new tranny is vacuum modulated, but shift points are still controlled thru the ECM, right. What else could effect when the tranny decides to shift. I've modified the normal shift mph, WOT shift mph, and WOT shift rpm setpoints, but it's still overshooting by a lot.


I've had one person mention that the '98 cars went off input shaft speed to determine shift time. I'm gonna log this morning and see how engine and input shaft RPM correlates.

Another person mentioned more fluid. The level is dead on full hot now, but I can add some more and see what happens.

Any other ideas?
Thanks

[JasonB]

With a stall speed like that you need to lower the commanded shift points.
Even stock settings with a stock converter don't match up.

[MNR-0]

Thats right. I got a stock converter and have to allow for 500RPM slip between commanded shift and actual shift and in all gears.