GM Service Manual Online
For 1990-2009 cars only

In 3rd gear, the rotations of the rear sun gear and the rear internal gear are the same, which means the rear planetary unit rotates as a unit and the sun gear RPM equals the internal gear RPM which equals the carries gear RPM. Therefore, the input and output axes are linked directly.


Object Number: 1282523  Size: MF
(1)Input Shaft (Rear Sun Gear)
(2)No Clutch
(3)Front Internal Gear
(4)Front Carrier
(5)Front Sun Gear
(6)High Clutch
(7)Rear Carrier
(8)Rear Internal Gear

3rd Gear


Object Number: 1282563  Size: LF

Pilot Pressure

Line pressure passes through the manual valve to shift valves A and B. Line pressure which has passed through shift valve A is applied to the 2-4 brake servo engagement side and shift valve B. Line pressure which has passed through shift valve B is applied to the low clutch and the servo release timing valve operational side. Line pressure which has passed through the manual valve to shift valve B is applied to the high clutch and the servo release timing valve. Line pressure which has passed through the servo release timing valve is applied to the 2-4 brake servo release side and releases the 2-4 brake. Therefore, the low clutch and the high clutch operate.