Transmission Shift Scheduling

Once the engine is started, the TCM updates the transmission oil temperature based on the following to determine an estimated oil temperature during vehicle operation (if a calculated oil temperature is being used):
- Torque converter slip speed
- Vehicle speed
- Engine coolant temperature
- Battery/ambient temperature

Vehicles with "calculated oil temperature" track oil temperature reasonably accurate during normal operation. However, if a transmission oil cooler is added, a transmission is overfilled, a transmission oil cooler becomes restricted or if a customer drives aggressively in low gear, the calculated oil temperature will be inaccurate. Consequently, the shift schedule selected may be inappropriate for the current conditions.

The key highlights of the various shift schedules are as follows:

Extreme Cold: Oil temperature at start up below -16° F.
- Goes to "Cold" schedule above - 12°F oil temperature
- Park, Reverse, Neutral and 2nd gear only (prevents shifting which may fail a clutch with frequent shifts)

Cold: Oil temperature at start up above - 12 ° F and below 36°F
- Goes to "Warm" schedule above 40° F oil temperature
- Delayed 2-3 upshift (approximately 22 - 31 MPH)
- Delayed 3-4 upshift (45 - 53 MPH)
- Early 4-3 coastdown shift (approximately 30 MPH)
- Early 3-2 coastdown shift (approximately 17 MPH)
- High speed 4-2, 3-2, 2-1 kickdown shifts are prevented
- No EMCC

Warm: Oil temperature at start up above 36° F and below 80° F
- Goes to "Hot" schedule above 80°F oil temperature
- Normal operation (upshift, kick-downs and coast-downs)
- No EMCC

Hot: Oil temperature at start up above 80° F
- Goes to "Overheat" schedule above 240° F oil temperature (250° F for 96 and prior MY)
- Normal operation (upshifts, kick-downs and coast-downs)
- Full EMCC, no PEMCC except to engage FEMCC (Except at closed throttle at speeds above 70 - 83 MPH)

Overheat: 96 and prior MY - Oil temperature above 250° F or engine coolant above 230°F
- Goes to "Hot" below 240° F oil temperature or "Super Overheat" above 260° F oil temperature
- Delayed 2-3 upshift (25 - 32 MPH) Delayed 3-4 upshift (41 - 48 MPH) 3rd gear FEMCC from 30 - 48 MPH 3rd gear PEMCC from 27 - 31 MPH

97 MY - Oil temperature above 240° F or engine coolant temperature above 244° F
- Goes to "Hot" below 230° F oil temperature or "Super Overheat" above 240° F oil temperature
- Delayed 2-3 upshift (25 - 32 MPH)
- Delayed 3-4 upshift (41 - 48 MPH)
- 3rd gear FEMCC from 30 - 48 MPH
- 3rd gear PEMCC from 27 - 31 MPH

Super Overheat: 97 MY - Oil temperature above 240°F
- Goes back to "Overheat" below 240 ° F oil temperature
- All "Overheat" shift schedules features apply 2nd gear PEMCC above 22 MPH
- Above 22 MPH the torque converter will not unlock unless the throttle is closed (i.e. at 50 MPH a 4th FEMCC to 3rd FEMCC shift will be made during a part throttle kickdown or a 4th FEMCC to 2nd PEMCC shift will be made at wide open throttle) or if a wide open throttle 2nd PEMCC to 1 kickdown is made.

96 and prior MY - Oil temperature above 260°F
- Goes back to "Overheat" below 260 ° F oil temperature
- All "Overheat" shift schedule features apply
- 2nd gear PEMCC above 22 MPH
- Above 22 MPH the torque converter will not unlock unless the throttle is closed (i.e. at 50 MPH a 4th FEMCC to 3rd FEMCC shift will be made during a part throttle kick-down or a 4th FEMCC to 2nd PEMCC shift will be made at wide open throttle) or if a wide open throttle 2nd PEMCC to 1 kickdown is made.

Causes for operation in the wrong temperature shift schedule:

Extreme Cold or Cold shift schedule at start up:
- Defective Engine Coolant Temperature Sensor (calculated oil temperature vehicles only)
- Defective Battery/Ambient Temperature Sensor (calculated oil temperature vehicles only)
- Defective PCM (calculated oil temperature vehicles only)
- Defective sensor circuit (TRS equipped only)

Overheat or Super Overheat shift schedule after extended operation:
- Operation in city traffic or stop-and-go traffic
- Engine idle speed too high - Stuck AIS motor
- Aggressive driving in low gear
- Trailer towing in OD gear position (use "3" position if frequent shifting occurs)
- Cooling system failure causing engine to operate over 230° F
- Engine coolant temperature stays low too long - If engine coolant temperature drops below 150° F. the transmission will disengage EMCC. Extended operation with the EMCC disengaged will cause the transmission to overheat.
- A defective brake switch will cause the EMCC to disengage. Extended operation with the EMCC disengaged will cause the transmission to overheat.
- Transmission fluid overfilled (TRS equipped only)
- Transmission cooler or cooler lines restricted (TRS equipped only)
- Defective sensor circuit (TRS equipped only)