Upshift Control & Torque Converter Clutch Apply

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The TCM calculates the upshift points based on throttle angle and the engine, turbine and output speed. When the TCM determines that conditions are met for a shift to occur, the TCM commands the shift and controls solenoid "A" and "B" current to properly control clutch pressures during the shift.

Choose a throttle angle of 10, 25 or 50 percent. All throttle angles shown should be tested to cover the normal driving range.
Monitor the following scan tool parameters:
- Throttle Angle
- Vehicle Speed
- Engine Speed
- Output Shaft Speed
- Commanded Gear
- Slip Speed
- Solenoid States
Place the gearshift lever in the Drive position.
Accelerate the vehicle using the chosen throttle angle. Hold the throttle steady.
As the transmission upshifts, note the vehicle speed when the shift occurs for each gear change. There should be a noticeable shift feel or engine speed change within 1-2 seconds of the commanded gear change.
Compare the shift speeds to the shift speed chart. Shift speeds may vary slightly due to transmission fluid temperature or hydraulic delays in responding to electronic controls. Note any harsh, soft or delayed shifts or slipping. Note any noise or vibration.
Repeat steps 1- 6 to complete all throttle angles.
Check for TCC apply in 2nd, 3rd, 4th and 5th gear. Note the TCC apply point. When the TCC applies, there should be a noticeable drop in engine speed and a drop in slip speed to below 100 RPM. If the TCC apply can not be detected, check for DTCs. Lightly tap and release the brake pedal. The TCC will release.