Wayne Cook
June 30, 2005

At the front pump, there's a brass bushing used to prolong service life.A small cut is made to the leading edge of the pump crescent. Thisquiets down the characteristic whining sound the C6 transmission makesat idle. A later model pump stator is used with CPT rebuilds becausethis stator offers improved lubrication qualities. Better lubricationand pump pressure means longer transmission life.

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Another durability improvement California Performance Transmission usesis special Teflon rings on the pump stator shaft, as well as the forwardclutch drum. The original steel rings are prone to excessive wear andhave a way of creating grooves where they aren't wanted. We tossed them.

The stock C6 valvebody is used, but it receives several modifications toreally be effective. Some are in-house secrets that we can't tell youabout. What we can say is CPT uses a larger accumulator spring forfurther improved second gear shift firmness. A larger pressure regulatorspring is used to increase line pressure, which also improves shiftquality and firmness. Further, CPT enlarges certain oil passageways inthe custom valvebody separator plate that improves high-gear shiftfirmness.

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Improvements to a CPT rebuild don't stop here. CPT also makes its ownhigh-performance torque converters in-house. They don't use inexpensivemetric converter covers, but rather they use their own assembly thatprovides a stall speed of about 2,500 rpm, depending on your performanceneeds. Stall speed is where the torque converter begins to transferengine power to the transmission. Choose your stall speed based on whereyour engine makes power. Street applications need a stall speed around1,800-2,500 rpm. Racers need higher stall speeds to get the engine intothe power band before torque multiplication and power transfer happen.

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