ENGINE AR-COMPLETE 1246730 - Caterpillar

Converter Drive Indicator
The Converter Drive Indicator feature will turn on a lamp (amber) when the transmission is in converter drive. The lamp will turn off when the transmission lockup clutch is engaged.Lockup Clutch Cycle Timer
To prevent stalling the engine, the torque converter lockup clutch is automatically cycled off when engine speed drops below a threshold. The lockup clutch will attempt to re-engage when conditions for LUC engagement are met. When operating at engine speeds near the LUC disengagement speed or at conditions which lug the engine below the LUC disengagement speed, the LUC may cycle off and on repeatedly. If this situation occurs more than five times in a 60 second period in the selected gear range, the transmission will be forced to downshift one gear. This function will protect the LUC from overheating. To resume normal shifting after a LUC protect downshift, the gear selector must first be downshifted to match the current transmission gear. The LUC cycle limiter is disabled in "1F" in order to avoid downshifting to neutral. Lockup Clutch Disable
To allow for fracturing pump pressure testing in torque converter drive, a lockup clutch disable feature is provided. The lockup clutch may be disabled via a J1939 controller command or by a hard wired switch depending on the OEMs preference. This feature disables the LUC in all ranges, but must be initiated while in Park , Neutral, or Stall. To prevent the transmission from operating continuously with the switch in the pressure test position, a Transmission Abuse Event shall be logged if the transmission is operating in converter drive for more than 30 seconds at an engine speed greater than 1700 rpm with the switch in the LUC disable (test) position. For applications using a switch to enable this feature, a fault in this circuit will trigger a diagnostic code. This circuit fault will also limit the transmission to Neutral and Park.Shift Inhibit
When an upshift is requested, the ECM monitors the following functions:
Engine speed
Torque converter output speed
Transmission output speed
Engine Load FactorThe ECM determines if the load factor is less than the desired threshold in order to allow the shift. The threshold is specified in order to ensure the following:
The desired gear is obtainable.
The lockup clutch can be engaged successfully.
The durability of the clutch is not affected.If the load factor is greater than the threshold, the ECM inhibits the upshift until a time when the specified conditions are met. Desired functions of the transmission may be inhibited for various reasons. The reasons are summarized in table 1. Additional Transmission Control Features
Table 1
Shift Control Function Reason for Inhibit Allowed Gear State Shift Inhibit Indicator
Neutral to park Transmission output shaft speed is greater than 1500 rpm.
or
The transmission input shaft speed is greater than 825rpm.
or
Quick to neutral switch selected Neutral N
Neutral to any gear Engine speed is greater than 1500 rpm.
or
The Quick to neutral switch is selected. Neutral N
Cold mode Trans oil temperature is less that 40