Twin Disc TA-90-8501, Operator'S Manual

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Twin Disc, Incorporated Description and Specifications
Power Shift Transmission System Operator’s Manual #1020510
Description
There are two main sections of the transmission, a countershaft input section,
and a planetary output section. The input section consists of three geared-
together clutch shafts and a driven front output shaft. A 9-inch ball dump clutch
is directly connected to, and driven by the input shaft, and when engaged, is
directly connected to the front output shaft. The outer member of this clutch
pack (gear driver) meshes with the input members of two shaft mounted clutches.
These clutches are 10.5 inch and are the
S type. When one of the input section
clutches is engaged, power is transmitted to the front output shaft either directly
or through the driven gears, and to the input members of the planetary output
section. There are three clutch pack assemblies in the planetary output section.
The high range clutch is a 12.5-inch and is of the
LD type. When engaged, the
output shaft rotates at the same speed as the front output shaft in the input
section of the transmission. There are two 23-inch planetary clutch assemblies
(non dump valve) that connect to the output flange through planetary reduction
gearsets. These are referred to as the low range and intermediate range clutch
pack assemblies
The hydraulic torque converter is a single stage Type 8 design with an integral
lockup clutch, and stator freewheel. The lockup clutch is hydraulically controlled
in conjunction with the electronic control.
Sump
The bottom of the transmission housing serves as the sump for all oil used in
the transmission/ torque converter system. A suction strainer is installed in the
sump to prevent debris from being drawn into the pump inlet.
Pump
The hydraulic system dual pump assembly is located on the rear of the torque
converter on a pump mount to the right of center as viewed from the rear. The
two pumps are of the positive displacement gear-type and are driven directly
by the engine. The pump inlets draw oil through a suction strainer. The oil from
the pumps is directed through filters and regulator valves and supplies pressure
for clutch apply, torque converter and lube. The pumps run at engine speed.
A scavenge pump is on the rear of the torque converter on a pump mount to the
left of center as viewed from the rear. The scavenge pump draws oil from the
bottom of the engine flywheel and converter housings and returns the oil to the
transmission sump.