HD785-7 POWER TRAIN Part 1-1

Compatible Unit Serial Number : 7001 and up 

STRUCTURE, FUNCTION
AND MAINTENANCE STANDART

for

POWER TRAIN (Part 1.1)

Power Train Skeleton

1. Engine (SAA12V140)
2. Output shaft
3. Front drive shaft
4. Brake cooling pump (SAR(4)180+180)
5. Torque converter, transmission + brake cooling and brake control pump (SDR(30)100+100+SAR(1)25)
6. PTO
7. Torque converter
8. Transmission
9. Rear drive shaft
10. Differential gear
11. Drive shaft
12. Brake
13. Tire
14. Final drive
15. Parking brake
16. Steering, hoist and hoist control pump (SAR(4)180+180+(1)6)

Output Shaft

1. Rubber cushion
2. Outer body
3. Flange
4. Shaft
5. Inner body
6. Cover

Function

The output shaft is installed to the engine flywheel, and absorbs the torsional vibration caused by changes in the engine torque.

No.	Check Item	Criteria (Unit: mm)						Remedy
1	Clearance between bearing and cover	Standart Size	Tolerance			Standart Clearance	Clearance Limit	Replace
			Shaft	Hole
		170	.0.015 -0.025	-0.008 -0.033		-0.033 0.017	-
2	Clearance between shaft and bearing	95	-0.015 -0.003	.0.00 -0.02		-0.017 -0.003	-
3	Clearance between bearing and cover	170	.0.015 -0.025	-0.008 -0.033		-0.033 .0.017	-
4	Clearance between bearing and shaft	95	+0.015 +0.003	.0.00 -0.02		-0.017 -0.003	-
5	Wear of oil seal contact surface of shaft	Standard size			Repair limit			Repair or Replace
		115			.0.015 -0.087
6	Defomation of rubber cushion	Original dimension: Lo			Standard backlash (Dimension at smallest width: L)			Replace
		90			81
		75			67
	External	No cracks

Drive Shaft

1. Front drive shaft
2. Rear drive shaft

Outline

• The power from the engine is transmitted through the output shaft, the front drive shaft (1) and the transmission, to the rear drive shaft (2).

Torque Converter and Transmission Hydraulic Piping

1. Torque converter
2. Transmission
3. Oil filler tube
4. Torque converter valve
5. Torque converter, transmission + brake cooling and brake control pump (SDR(30)100+100+SAR(1)25)
6. Transmission oil filter (4 pieces)
7. Brake cooling oil control valve

Brake Cooling Oil Control Valve (BCV)

   1. Pilot relief valve assembly
   2. Body
   3. Solenoid valve
   4. Main valve spool
   A: Pilot port
   B: Pilot port
   S: To transmission oil pan
   P: Pilot port
   Q: From pump
   R: To transmission oil pan

Function

When the retarder is not being used, this valve bypasses part of the brake cooling oil to reduce the power loss when traveling. The main valve spool (4) is actuated by switching the solenoid vavle (3) ON/OFF.

If abnormal pressure is generated in the retarder because of a trouble in the rear retarder, oil cooler, etc., pilot relief valve (1) operates to operate main valve spool (4). Accordingly, the brake cooling oil control valve (BCV) works as an unload valve, too. The figure shows the state when the brake is ON.

In this state, if the pressure of the oil from the pump is below the pilot pressure (9 kg/cm2), the brake cooling oil control valve does not bypass the brake cooling oil.