A modified hydraulic circuit for an OEM vehicle transmission, which transmission has a forward clutch, a forward clutch hub and a forward sprag having an inner sprag race and an outer sprag race, an overrun clutch and an overrun clutch hub, the forward clutch and the forward sprag providing a link to a planetary gear train to propel the vehicle forward, the forward clutch hub defining the outer sprag race, the overrun clutch hub defining the inner sprag race, a hydraulic valve body having a plurality of passages and a separator plate, and a 1-2 shift valve, a 2-3 shift valve, a 3-4 shift valve and a 3-4 relay valve, and a gear shift valve, includes a blockage in the passage fluidically connecting the 2-3 shift valve to the overrun clutch, a blockage in the passage fluidically connecting the gear shift valve to the 2-3 shift valve, removal of a movable element from the first check valve body and a passage from the gear shift valve to the overrun clutch via the first check valve body, wherein when operating in the D4 mode, the forward clutch is applied and the overrun clutch is applied and are locked to one another, such that the forward sprag clutch is ineffective. A method of modifying the hydraulic circuit is disclosed.

The present invention solves bore wear due to inefficient design of OEM pressure regulator valve through an improved pressure regulator valve with lands having narrower diameters and longer lengths, the lands additionally having a grooved design, and a second land having a beveled edge to stabilize fluid regulation. Narrower lands allow for better ATF lubrication in a bore. Longer lands allow for the valve to be dropped into a bore to interact with non-damaged lengths of the bore without further machining. The beveled edge regulates pressure, further reducing bore wear.

A method of adjusting and using operating parameters of a transmission of a vehicle may include accessing a stored list of clutch parameters, performing a dynamic condition procedure while the vehicle is driven to revise minimum on-coming apply pressure for each friction element based on a sensed performance of an element within the vehicle powertrain, storing the modified minimum on-coming apply pressures, and operating the vehicle. A related transmission control device operates a transmission using parameters obtained during a dynamic condition procedure.

A method for modifying the hydraulic circuitry of factory installed 46RE, 47RE and 48 RE automotive transmissions internally re-routes the flow of hydraulic fluid within the valve body of the automotive transmission to improve the overall operation of these factory installed automotive transmissions, without adding or installing any external passageway structures to the valve body. The internal re-routing of the hydraulic flow within the valve body is accomplished by replacing the existing separator plate with one or more new cooperating separator plates, and by plugging portions of the existing hydraulic circuitry, to internally re-route the flow of hydraulic fluid within the valve body by blocking certain existing internal hydraulic circuitry and by creating new internal hydraulic circuitry for fluid flow within the valve body. The modified 46RE and 47RE transmissions exhibit improved operating characteristics, simulating the operation of a 48RE automotive transmission.

Methods for modifying certain prior art automatic transmissions to strengthen the transmission and eliminate a tendency of the transmissions to fail as well as components for doing the same. Some aspects also include kits for modifying a transmission to increase the strength of the transmission. In some examples, the hydraulic system of a General Motor's model number 4L80E transmission is modified so that an overrun clutch is engaged in more modes of operation than the original equipment prior art 4L80E transmission in order to minimize a tendency for an overdrive roller clutch to fail.

A method of adjusting operating parameters of a transmission of a vehicle may include accessing a stored list of clutch parameters; performing a static condition procedure to revise the clutch parameters; and performing a dynamic condition procedure to further revise the clutch parameters. The method may be performed by a transmission control device for the vehicle, the vehicle having a powertrain including an engine, the transmission with a plurality of solenoid actuated friction elements, and sensors. The static condition procedure and dynamic procedures may be performed incrementally, and the static condition procedure may be performed more than once to fine tune the results.

The hydraulic circuitry of a factory installed automatic automotive transmission is modified to replace an underdrive accumulator spring with a shorter spring and a separate lower rated spring washer operatively associated with the shorter replacement underdrive accumulator spring. The combined replacement spring and spring washer conjointly act on an underdrive accumulator piston to move it in two predetermined distances, in two separate continuous stages, namely, movement of the piston for a first predetermined distance is controlled by the spring washer, while movement of the piston for a second predetermined distance is controlled by the replacement spring. The spring washer has a lower spring rating than the replacement spring, so that less fluid pressure is required to move the piston the total distance traveled, resulting in less fluid pressure applied to an underdrive clutch than in the factory installed transmission. The spring ratings of the replacement spring and the spring washer are selected such that the total fluid pressure required to move the piston both the first and second predetermined distances is less than the fluid pressure required to overcome the resilient force of underdrive piston return springs acting on an underdrive apply piston so that a lower fluid pressure is applied to an underdrive clutch.

Aspects of the present disclosure include methods of modifying a transmission valve body to increase a line pressure response in certain hydraulic shift control system configurations. In one example, a Daimler Chrysler 46RE or 47RE transmission valve body may be modified to have a higher and more rapid line pressure increase when the transmission is in fourth gear and when the torque converter clutch (TCC) is engaged. Aspects of the present disclosure also include methods of modifying a transmission valve body to allow TCC engagement in any gear. Aspects of the present disclosure also include replacement valve bodies, as well as kits for modifying a 46RE or 47RE valve body to perform like a 48RE valve body.

A method of rebuilding a pressure control solenoid includes uncrimping a housing of the solenoid, and disassembling the solenoid. An original spool valve of the solenoid is removed from a hydraulic bore of the solenoid. The hydraulic bore is reamed such that an inner diameter of the bore is enlarged. A replacement spool valve is inserted into the hydraulic bore. An outer diameter of the replacement spool valve is larger than an outer diameter of the original spool valve.

A method of adjusting operating parameters of a transmission of a vehicle may include accessing a stored list of clutch parameters; performing a static condition procedure to revise the clutch parameters; and performing a dynamic condition procedure to further revise the clutch parameters. The method may be performed by a transmission control device for the vehicle, the vehicle having a powertrain including an engine, the transmission with a plurality of solenoid actuated friction elements, and sensors. The static condition procedure and dynamic procedures may be performed incrementally, and the static condition procedure may be performed more than once to fine tune the results.