Any Tutorials for tuning an auto tranny?

[joecar]

Howard,

When you say to increase the base shift pressure, are you implying the following paramters; D0701, D0702 and D0703?

Yes, those ones.

How does the desired shift time work? When does the time start, that is controlled by parameters D1108, D1109 and D1110?

The PCM initiates the shift and monitors the time taken for the engine rpm to drop the correct amount for the gear ratio;
the PCM compares the time taken with the desired shift time and adjusts ("adapts", "learns") the line pressure for the next time this same shift occurs.
If you reduce shift time and the log consistently shows otherwise, then don't reduce it any further (increase it until log concurs).
As Ross said, some cars have learning, some don't.

Appreciate the information but I just want to know what I am changing and not just to make the change!

Make small changes, log data and display as both charts and maps to get a better picture of what happens
(e.g. be creative with maps: shift time (vss vs tps), shift error (vss vs tps), etc...).

Anything with the forced motor current function?

D3801 this table represents the physical capability of the pressure control solenoid (PCS, a.k.a. torque force motor, TFM);
GM filled in this table by measuring the pressure regulated by the PCS (after first calibrating the PCS);
it's best to leave this table alone
(unless you modify the PCS by turning the calibration screw [bad idea];
it's possible to tweak this table if you use a pressure gauge and you're able to keep the trans.
at a constant temp while you measure the range of pressures produced by the current range (Scan Tool BiDir mode);
Note: as current goes down, pressure goes up).

[joecar]

I've never liked the part throttle shift from 1-2, it was always too hard. I've softened it by increasing shift times, but still a little too firm around town. All the WOT shifts feel good, BTW.

In table D0801, increase the torque reduction for the lower values of delivered engine torque and see if this softens the around town PT 1-2 shift.