GMC 1976 ZEO 6083 Maintenance Manual page 449

Contents of this section are listed below:
SUBJECT PAGE N0 .
General Information . ... . . ... . .... . . .. . . . .. . . ... . .... . ... . .... .... . ... . .... . ... . . .. . . . ... . .... . . .. . . . .. . . .... . ... . . ... . . .. . . . .. . . .. .7-1
Trouble Diagnosis ... . . .. . . . ... . .... . ... . . . .. . . ... . .... . ... . ... . .... . ... . .... .... . . .. . . . ... . .... . ... . . . .. . . ... . . ... . . . .. . . .. . . . . . . . . 7-10
On Vehicle Servicing . .... . ... . . ... . . .. . . . .. . . .... .... . ... . .... . ... . ... . . ... . . .. . . . .. . . .... . ... . . . . . . . ... . .... . ... . . . .. . . .. . . . .. . . . 7-25
Transmission Replacement .... . ... . . ... . . ... . .... . ... . ... . ... . . ... . ... . .... . ... . . . .. . . .... . ... . . . .. . . ... . . ... . . . .. . ... . . .. . . . . 7-29
Transmission Overhaul . . ... . .... . . .. . . . .. . . ... . .... . ... . .... . ... . ... . .... . ... . . ... . . ... . . ... . . . . . . . ... . .... . . . . . . ... . . .. . . . .. . . . 7-32
Transmission Specifications .... . ... . . .. . . . .. . . ... . . . .. . ... . ... . . .. . . ... . .... . ... . . . .. . . .... . . .. . . . .. . . ... . . ... . .... . ... . . .. . ... 7-74
Special Tools . . . . . . . .... .... . ... . . . .. . . ... . . ... . .... . ... . . ... . ... . . .. . . .. . . ... . . ... . . ... . .... . . .. . . . ... . .... . . .. . . . .. . . .. . . .... . . .. . ... 7-74
GENERAL INFORMATION
DESCRIPTION
The Turbo Hydra-Matic transmission, Figure l,
is a fully automatic transmission used for front wheel
drive applications .
The Turbo Hydra-matic transmission consists
primarily of a three-element hydraulic torque con-
verter, a dual sprocket and link assembly and a com
pound planetary gear set. Three multiple-disc
clutches, a sprag unit, a roller clutch unit, and two
bands provide the friction elements required to ob-
tain the desired functions of the compound planetary
gear set.
The torque converter, the dual sprocket and link,
the clutches, the sprag and roller clutch, couple the
engine to the planetary gears, providing three for
ward speeds and one reverse. The torque con-
verter when required will supplement the gears by
multiplying engine torque .
The torque converter is of welded construction and
is serviced as an assembly . The unit is made up of two
vaned sections, or halves, that face each other in an
oil filled housing. The pump half of the converter is
connected to the engine and the turbine half is, in
effect, connected to the transmission .
The torque converter couples the engine to the
planetary gear set through the use of a drive
sprocket, a link assembly, and a driven sprocket .
Clockwise engine torque turns the drive sprocket
clockwise, which, in turn, drives the driven sprocket
in a clockwise direction. This in effect is a reverse in
the direction of engine torque due to the side mount-
ing of the gear unit .
SECTION 7
TRANSMISSION
TRANSMISSION 7- 1
When the engine makes the converter pump re-
volve, it sends oil against the turbine, making it re-
volve also . The oil then returns in a circular flow
back to the converter pump, continuing this flow as
long as the engine is running.
The converter also has a smaller vaned section,
called a stator, that funnels the oil back to the con-
verter pump through smaller openings, at increased
speed. The speeded up oil directs additional force to
the engine-driven converter pump, thereby multiply-
ing engine torque .
A hydraulic system pressurized by an internal-
external type gear pump provides the working pres-
sure required to operate the friction elements and
automatic controls .
are:
External control connections to the transmission
Manual Linkage-To select the desired operat-
ing range.
Engine Vacuum-To operate a vacuum 'modula-
tor unit .
12 Volt Electrical Signal-To operate an electri-
cal detent solenoid .
Gear or Torque ratios of the transmission are as
follows:
First = 2.48:1 gear ratio
Second = 1 .48:1 gear ratio