lane assist CHEVROLET CAMARO 1967 1.G Chassis Workshop Manual

CLUTCH AND TRANSMISSIONS 7-36

TURBO HYDRA-MATIC TRANSMISSION

INDEX

Page

General Description . . , . 7-36

Maintenance and Adjustments . 7-37

Transmission Fluid 7-37

Fluid Level Indicator 7-37

Shift Control Linkage Adjustment ........... 7-37

Neutral Safety Switch Adjustment 7-37

Draining and Refilling Transmission . . . 7-37

Pressure Regulator Valve 7-38

Control Valve Body . 7-39

Governor ..'.... 7-40

Modulator and Modulator Valve 7-40

Parking Linkage . . 7-40
Page

Rear Seal -. 7-40

Other Service Operations . . 7-40

Transmission Replacement 7-40

Turbo Hydra-Matic Diagnosis Procedure. ......... 7-41

Sequence . ; ; 7-41

Oil Level and Condition Check 7-41

Manual Linkage 7-41

Oil Leaks .' 7-41

Case Porosity - Repair ................ 7-42

Oil Pressure Check 7-42

Transmission Shift Points 7-42

Special Tools 7-43

GENERAL DESCRIPTION

The Turbo Hydra-Matic transmission is a fully auto-

matic unit consisting primarily of a 3-element hydraulic

torque converter and a compound planetary gear set.

Three multiple-disc clutches, one sprag unit, one roller

clutch and two bands provide the friction elements re-

quired to obtain the desired function of the compound

planetary gear set.

The torque converter couples the engine to the plane-

tary gears through oil and provides hydraulic torque

multiplication when required. The compound planetary

gear set produces three forward speeds and reverse.

The
3-
element torque converter consists of a pump or

driving member, a turbine or driven member, and a

stator assembly. The stator is mounted on a one-way

roller clutch which will allow the stator to turn clock-

wise but not counter-clockwise.

The torque converter housing is filled with oil and

is attached to the engine crankshaft by a flex plate and

always rotates at engine speed. The converter pump is

an integral part of the converter housing, therefore the

pump blades, rotating at engine speed, set the oil within

the converter into motion and direct it to the turbine,

causing the turbine to rotate.

As the oil passes through the turbine it is traveling in

such a direction that if it were not re-directed by the

stator it would hit the rear of the converter pump blades

and impede its pumping action. So at low turbine speeds,

the oil is re-directed by the stator to the converter pump

in such a manner that it actually assists the converter

pump to deliver power or multiply engine torque.

As turbine speed increases, the direction of the oil

leaving the turbine changes and flows against the rear

side of the stator vanes in a clockwise direction. Since

the stator is now impeding the smooth flow of oil, its

roller clutch releases and it revolves freely on its shaft.

Once the stator becomes inactive, there is no further

multiplication of engine torque within the converter. At

this point, the converter is merely acting as a fluid

coupling as both the converter pump and turbine are

being driven at approximately the same speed - or at a

one-to-one ratio.

A hydraulic system pressurized by a gear type pump

provides the working pressure required to operate the

friction elements and automatic controls.

External control connections to transmission are:
Manual Linkage

Engine Vacuum

12 Volt Electrical

Signal
To select the desired op-

erating range.

To operate a vacuum mod-

ulator unit.

To operate an electrical

detent solenoid.

A vacuum modulator is used to automatically sense

any change in the torque input to the transmission. The

vacuum, modulator transmits this signal to the pressure

regulator for line pressure control, to the 1-2 accumula-

tor valve, and to the shift valves so that all torque re-

quirements of the transmission are met and smooth

shifts are obtained at all throttle openings.

The detent solenoid is activated by an alectric switch

on the carburetor. When the throttle is fully opened, the

switch on the carburetor is closed, activating the detent

solenoid and. causing the transmission to downshift at

speeds below approximately 70 MPH.

The selector quadrant has six selector positions: P,R,

N,D,
L2,L1.

P.
*
- Park position positively locks the output shaft to

the transmission case by means of a locking pawl

to prevent the vehicle from rolling in either di-

rection. The engine may be started in Park

position.

R. - Reverse enables the vehicle to be operated in a

reverse direction.

N.
- Neutral position enables the engine to be started

and run without driving the vehicle.

D,
- Drive Range is used for all normal driving condi-

tions and maximum economy. Drive Range has

three gear ratios, from the starting ratio to

direct drive. Detent downshifts are available by

depressing the accelerator to the floor.

L2.
- L2 Range has the same starting ratio as Drive

Range, but prevents the transmission from shift-

ing above second speed to retain second speed

acceleration when extra performance is desired.

L2 Range can also be used for engine braking.

L2 Range can be selected at any vehicle speed,

and the transmission will shift to second gear and

remain in second until the vehicle speed or the

throttle are changed to obtain first gear operation

in the same manner as in D Range.

CHIVROLET CHASSIS SERVICE MANUAL