Service Manual User Manual

Section 7
7-2
Introduction
Legend
Model 3606 • Origin 10/99
1. Dipstick Assembly
2. Dipstick Tube
3. Plug
4. O-ring
5. Sensor Port Plug
6. Oil Level Plug
7. Oil Level Plug O-ring
8. Transmission Case
9. Tube and Screen Assembly
10. Oil Supply Tube Seal Ring
11. Oil Supply Tube Retainer Clip
12. Seal Washer
13. Clip Retainer Screw Nut
14. Clip Retainer Screw Washer
15. Retainer Clip Screw
16. Magnetic Drain Plug
17. Screw
18. Converter Housing-to-Plate Gasket
19. Converter Housing
20. Temperature Pickup Plug
21. Lock Washer
22. Screw
23. Screw
24. Plug
25. Plug
26. Screw
27. Screw
28. Safety Valve Seat
29. Safety Valve Spring
30. Poppet Washer
31. Sensor O-ring
32. Sensor Port Plug
33. Speed Sensor Plug Screw
34. Spacer Plate
35. Seat Snap Ring
36. Converter Safety Valve Poppet
37. Drain Back Port Plug
38. Spacer Plate-to-Transmission Case
Dowel Pin
39. Spacer Plate-to-Transmission Case
Gasket
40. Transmission Case-to-Spacer Plate
Screw
41. Filler Plug
42. Air Breather
43. Transmission Gasket and Sealing Kit
(services entire transmission)
Instructions in this section pertain mainly to general
specifications, towing, maintenance information, and
transmission removal and installation procedures.
Internal transmission service instructions and detailed
specifications are provided in the Clark-Hurth T 12000
Powershift Transmission 3, 4, & 6 Speed Intermediate
Drop Maintenance and Service Manual, part number SM
T12-3,4,6 ID.
The Clark-Hurth T 12000 Powershift Transmission used in
this vehicle is available in four-speed (Cummins and Per-
kins turbocharged engines) and three-speed (Perkins nat-
urally-aspirated engines) configurations. One gear select
lever is used for both applications; of course, a fourth gear
will not be present if the vehicle is equipped with a three-
speed transmission. The “intermediate drop” designation
refers to the relative top-to-bottom length of the transmis-
sion case, chosen for its compatibility with vehicle chassis
and operating requirements. Intermediate drop does not
refer to an operational RPM shift or drop.
The flywheel provides engine input to the transmission
and, ultimately, out of the transmission to the transfer case
and drive axles. Hydraulic power flows through the trans-
mission and torque converter, which is attached to the fly-
wheel. The transmission and hydraulic torque converter
operate together to transmit engine power to the axles via
the transfer case (“drop box”) and drive shafts. The trans-
mission and torque converter are powered by their own
internal hydraulic (“transmission fluid”) system, separate
from the vehicle hydraulic system. The transmission is
equipped with an external oil cooler, mounted in the
engine heat exchanger (radiator).
The transmission gear (or “speed”) select lever, an electric
shift control, is located on the left side of the steering col-
umn in the operator's cab. Movement of the gear select
lever energizes the selected transmission shift solenoid
valves, which, in turn, direct the transmission fluid under
pressure to the selected forward or reverse valve, and to
the designated range (gear or “speed”) clutch. Several fac-
tors, including terrain, loading, engine RPM, axle/wheel-
end gearing and the selected transmission gear determine
actual vehicle speed.
To engage the clutch, the gear select lever is placed in the
desired directional (forward or reverse) and range (gear or
“speed”) position. Gear select lever movement energizes
the selected direction and range (gear) solenoids, allowing
transmission fluid under pressure to flow through tubes
and passages to the selected clutch shafts. Oil sealing
rings are located on the clutch shaft; these rings direct oil
under pressure through a drilled passageway in the shaft
to a desired clutch. Hydraulic pressure forces the piston
and discs against the back-up plate. Discs, with edge
tangs, clamp against toothed discs on the inner diameter,
enabling the hub and the clutch shaft to lock together and
drive as a unit, providing output power.