Methods of modifying a GM Powerglide low range servo assembly for high line pressure applications as well as replacement components for Powerglide low range servo assemblies and replacement low range servo assemblies.

The hydraulic circuitry of the factory installed automotive automatic transmission of the General Motors Corporation identified as the Allison 1000 and 2000 Series is modified to include a new return spring to decrease clutch pressure and mainline pressure so as not to exceed a predetermined pressure to reduce the time to complete an upshift, to replace the main regulator valve spring to increase main line pressure at road speed based on road conditions, and to provide a new valve with an internal exhaust circuit operatively associated with the TCC (Torque Converter Clutch) to lower balance circuit pressure resulting in the increase of converter clutch apply pressure. The methods and systems for modifying the factory installed transmissions improve the overall operation and efficiency of the transmission during operation of the motor vehicles in which the transmissions are installed.

A system for modifying an automatic transmission of a vehicle which has a plurality of clutch packages to provide a low gear and a plurality of high gears and a transmission control module equipped to run the transmission in a normal start gear mode with shifting beginning from low gear and progressing to the higher gears and a higher start gear mode beginning at one of the higher gears, wherein the system includes a clutch brake mechanism connected to the transmission which when actuated on during initiation of the higher start gear mode, applies increased pressure on a predetermined clutch package creating a temporary clutch brake to keep in check clutch packages engaged for the higher start gear mode, and upon actuating off releases the predetermined clutch package thereby enabling enhanced take off speed with the high gear clutch packages being engaged.

A method for controlling a motor vehicle transmission having a transmission actuator to actuate the vehicle transmission, having a vehicle clutch with a clutch actuator to actuate the vehicle clutch, having a first control unit which has a memory area that is unambiguously assigned to it, having a second control unit which has a memory area that is unambiguously assigned to it.

The hydraulic circuitry of the factory installed automotive automatic transmission of the General Motors Corporation identified as the Allison 1000 and 2000 Series is modified to include a new return spring to decrease clutch pressure and mainline pressure so as not to exceed a predetermined pressure to reduce the time to complete an upshift, to replace the main regulator valve spring to increase main line pressure at road speed based on road conditions, and to provide a new valve with an internal exhaust circuit operatively associated with the TCC (Torque Converter Clutch) to lower balance circuit pressure resulting in the increase of converter clutch apply pressure. The methods and systems for modifying the factory installed transmissions improve the overall operation and efficiency of the transmission during operation of the motor vehicles in which the transmissions are installed.

The hydraulic circuitry of a factory installed automatic automotive transmission is modified to include a check ball and spring to limit balance oil to a predetermined pressure applied to first end of the clutch regulator valve. When the onboard automobile computer ramps up solenoid oil pressure applied to the clutch regulator valve through a gain valve that acts on a first end of the clutch regulator valve, this pressure is opposed by a spring as well as clutch balance oil pressure that is routed and applied to a second opposite end of the clutch regulator valve. The arrangement limits the balance oil pressure applied to the second end of the clutch regulator valve to a predetermined maximum value so the onboard computer regulates the clutch up to that predetermined value. When the pressure/force applied to the second end of the clutch regulator valve exceeds the predetermined maximum value, a check ball disposed at the second end of the clutch regulator valve, held in place by a spring, is displaced and unseated from a seat in a valve bore, resulting in the exhaust or leaking of the balance oil applied to the second end of the clutch regulator valve so that the oil pressure applied to the first end of the clutch regulator valve is no longer opposed by the balance oil applied to the second end of the clutch regulator valve, thereby enabling the clutch regulator valve to quickly move in a direction to complete the shift and to hold added engine power during the shift.

A method for adapting a pressure characteristic curve of a friction-locking shift element of a transmission of a motor vehicle includes actuating the shift element using a rapid filling pressure for a first time, shorter than an adapted rapid filling time by a defined period of time. The method further includes subsequently actuating the shift element using a waiting pressure for a waiting time, the waiting pressure being lower than the rapid filling pressure. The method further includes subsequently actuating the shift element using the rapid filling pressure during a second time, equal to the defined period of time, and ascertaining a reaction of the transmission to adaptation. Additionally, the method includes determining, when the reaction of the transmission to the adaptation corresponds to a reaction to the rapid filling time adaptation, a pressure at a characteristic point on the curve being adapted as the waiting pressure.

The hydraulic circuitry of the factory installed automotive automatic transmission of the General Motors Corporation identified as the Allison 1000 and 2000 Series is modified to include a new return spring to decrease clutch pressure and mainline pressure so as not to exceed a predetermined pressure to reduce the time to complete an upshift, to replace the main regulator valve spring to increase main line pressure at road speed based on road conditions, and to provide a new valve with an internal exhaust circuit operatively associated with the TCC (Torque Converter Clutch) to lower balance circuit pressure resulting in the increase of converter clutch apply pressure. The methods and systems for modifying the factory installed transmissions improve the overall operation and efficiency of the transmission during operation of the motor vehicles in which the transmissions are installed.

Three operational defects in the 8L series transmission, individually or in combination, produce a shudder complaint and potentially damage the torque converter. An incorrectly ported torque converter control valve is corrected by increasing length of an undersized third land to prevent mixing of three adjacent flow channels and a loss of lockup apply pressure. Start time of a torque converter enable valve regulation cycle is rescheduled to avoid causing excessive rear side pressure drop and significantly shortening time required to pressure up apply side of a converter clutch. A lockup solenoid is replaced with an anti-ballooning assembly to better control pressure and avoid complete transmission failure.

A method for adapting a pressure characteristic curve of a friction-locking shift element of a transmission of a motor vehicle includes actuating the shift element using a rapid filling pressure for a first time, shorter than an adapted rapid filling time by a defined period of time. The method further includes subsequently actuating the shift element using a waiting pressure for a waiting time, the waiting pressure being lower than the rapid filling pressure. The method further includes subsequently actuating the shift element using the rapid filling pressure during a second time, equal to the defined period of time, and ascertaining a reaction of the transmission to adaptation. Additionally, the method includes determining, when the reaction of the transmission to the adaptation corresponds to a reaction to the rapid filling time adaptation, a pressure at a characteristic point on the curve being adapted as the waiting pressure.