784C and 785C Off-Highway Truck/Tractors Power Train Caterpillar

Specifications (Power Train)

Usage:

785C 1HW

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Table 1
Shift Points At Nominal Engine Speed
Upshift	Engine Speed	Transmission Output Speed
1C to 1L	1635 ± 50	366
1L to 2	1855 ± 30	495
2 to 3	1855 ± 30	668
3 to 4	1840 ± 30	905
4 to 5	1840 ± 30	1222
5 to 6	1840 ± 30	1657

Downshift	Engine Speed	Transmission Output Speed
6 to 5	1290 ± 30	1569
5 to 4	1290 ± 30	1162
4 to 3	1290 ± 30	856
3 to 2	1290 ± 30	634
2 to 1L	1300 ± 30	468
1L to 1C	1262 ± 30	336

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Table 2
Maximum Travel Speeds at 1900 rpm (33.00-R51 tires)
Gear	Speed
R	10.9 km/h (6.8 mph)
1	12.1 km/h (7.5 mph)
2	16.3 km/h (10.1 mph)
3	22.2 km/h (13.8 mph)
4	29.9 km/h (18.6 mph)
5	40.6 km/h (25.2 mph)
6	54.8 km/h (34.0 mph)

Specifications for the Torque Converter

Outlet Relief Valve

Pressure setting of the outlet relief valve ... 550 ± 35 kPa (80 ± 5 psi)

Torque converter outlet pressure at stall speed ... 345 to 550 kPa (50 to 80 psi)

Torque converter stall speed at operating temperature ... 1640 ± 65 rpm

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Table 3
Spacer Chart for the Outlet Relief Valve
Pt. No. for the Spacers	Thickness of the Spacers	Change in Pressure as a result of one Spacer
5M-9624 Spacer	.25 mm (0.01 inch)	5 kPa (0.73 psi)
5M-9623 Spacer	.90 mm (0.035 inch)	18 kPa (2.61 psi)

Inlet Relief Valve

Pressure setting for the inlet relief valve ... 930 ± 35 kPa (135 ± 5 psi)

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Table 4
Spacer Chart for the Inlet Relief Valve
Pt. No. for the Spacers	Thickness of the Spacers	Change in Pressure as a result of one Spacer
5M-9624 Spacer	.25 mm (0.01 inch)	14 kPa (2.0 psi)
5M-9623 Spacer	.90 mm (0.035 inch)	49 kPa (7.1 psi)

Torque Converter Hydraulic Filter

Pressure setting for the bypass valve ... 140 kPa (20 psi)

Torque Converter and Front Brake Cooling Screen

Pressure setting for the bypass valve ... 248 ± 21 kPa (36 ± 3 psi)

Parking and Secondary Brake Valve

Parking brake release pressure at high idle ... 4690 ± 200 kPa (680 ± 29 psi)

Parking Brake Release Hydraulic Filter

Pressure setting for the bypass valve ... 248 ± 21 kPa (36 ± 3 psi)

Lockup Clutch and Synchronizing Valve

Pressure Reduction Valve

Pilot pressure at low idle ... 1725 ± 70 kPa (250 ± 10 psi)

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Table 5
Chart of Shims for the Pressure Reduction Valve
Pt. No. for the Shims	Thickness of the Shims	Change in Primary Pressure as a result of one Shim
5J-2721 Shim	.13 mm (0.005 inch)	10 kPa (1.4 psi)
6J-3993 Shim	.25 mm (0.01 inch)	19 kPa (2.8 psi)
5J-1036 Shim	.80 mm (0.031 inch)	60 kPa (8.7 psi)

Modulation Reduction Valve

Pressure at low idle ... 2135 ± 70 kPa (310 ± 10 psi)

Minimum pressure at 1300 rpm ... 2135 kPa (310 psi)

Lockup clutch primary pressure at low idle ... 1030 ± 35 kPa (150 ± 5 psi)

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Table 6
Chart of Shims for the Modulation Reduction Valve⁽¹⁾
Pt. No. for the Shims	Thickness of the Shims	Change in Primary Pressure as a result of one Shim
8J-4452 Shim	.12 mm (0.005 inch)	10 kPa (1.4 psi)
2S-0675 Spacer	.40 mm (0.016 inch)	32 kPa (4.6 psi)
9J-1330 Shim	.79 mm (0.031 inch)	62 kPa (8.9925 psi)

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⁽¹⁾	Before an adjustment is performed, be certain that the valve springs are not weak or broken.

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Table 7
Speed	Engaged Clutches	Torque Converter Drive	Direct Drive (Engaged Lockup Clutch)
Neutral-1	3	X	-
Neutral-2	1	X	-
Reverse	1 and 6	X	-
First Gear	1 and 5	X	X
Second Gear	2 and 5	-	X
Third Gear	1 and 4	-	X
Fourth Gear	2 and 4	-	X
Fifth Gear	1 and 3	-	X
Sixth Gear	2 and 3	-	X

Transmission

Pressure Control Valve

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Table 8
Station⁽¹⁾	A	B	C	D⁽²⁾	E	F	G
Engaged Clutch	2	1	3		4	5	6
Type of Test	Pressure
Clutch Pressure At High Idle In Torque Converter Drive		2890 kPa (419 psi)⁽³⁾	2470 kPa (358 psi)⁽⁴⁾			2705 kPa (392 psi)⁽⁴⁾	2805 kPa (407 psi)⁽⁴⁾
Clutch Pressure At Low Idle In Torque Converter Drive⁽⁴⁾		2760 kPa (400 psi)				2705 kPa (392 psi)⁽⁴⁾	2760 kPa (400 psi)⁽⁴⁾
Clutch Pressure At High Idle In Direct Drive⁽⁴⁾	2020 kPa (293 psi)	2020 kPa (293 psi)	2020 kPa (293 psi)		2020 kPa (293 psi)	2020 kPa (293 psi)
Primary Clutch Pressure At Low Idle⁽⁵⁾	525 kPa (76 psi)	475 kPa (69 psi)	480 kPa (70 psi)		425 kPa (62 psi)	450 kPa (65 psi)	425 kPa (62 psi)

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⁽¹⁾	Station "H" is not used.
⁽²⁾	Station "D" does not control a clutch. Station "D" controls the dual stage relief valve for the system pressure.
⁽³⁾	The tolerance is ± 225 kPa (± 33 psi).
⁽⁴⁾	The tolerance is + 240 − 100 kPa (+ 35 − 15 psi).
⁽⁵⁾	The tolerance is + 50 − 35 kPa (+ 7 − 5 psi).

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Table 9
(1) Shims for the Pressure Control Valve Pressure Change per Shim
Station⁽¹⁾	A	B	C	D⁽²⁾	E	F	G
Engaged Clutch	2	1	3	-	4	5	6
Thickness of Shim	Pressure Change	Pressure Change	Pressure Change	Pressure Change	Pressure Change	Pressure Change	Pressure Change
5J-2721 Shim
0.13 mm (0.005 inch)	20 kPa (2.9 psi)	17 kPa (2.5 psi)	20 kPa (2.9 psi)	12 kPa (1.7 psi)	17 kPa (2.5 psi)	14 kPa (2.0 psi)	19.5 kPa (2.83 psi)
6J-3993 Shim
0.25 mm (0.010 inch)	41 kPa (5.9 psi)	33 kPa (4.8 psi)	41 kPa (5.9 psi)	25 kPa (3.6 psi)	35 kPa (5.1 psi)	28 kPa (4.1 psi)	38.5 kPa (5.58 psi)
4M-1751 Spacer
0.41 mm (0.016 inch)	65 kPa (9.4 psi)	53 kPa (7.7 psi)	65 kPa (9.4 psi)	39 kPa (5.7 psi)	56 kPa (8.1 psi)	45 kPa (6.5 psi)	62 kPa (9.0 psi)
5J-1036 Shim
0.80 mm (0.031 inch)	125 kPa (18.2 psi)	103 kPa (14.9 psi)	125 kPa (18.2 psi)	76 kPa (11.0 psi)	109 kPa (15.8 psi)	87 kPa (12.6 psi)	120 kPa (17.4 psi)

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⁽¹⁾	Station "H" is not used.
⁽²⁾	Station "D" does not control a clutch. Station "D" controls the dual stage relief valve for the system pressure.

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Table 10
Specifications and Identification of the Components of the Pressure Control Valve
Location of the Load Piston Body⁽¹⁾	A	B	C	D	E	F	G
Thickness of the Load Piston Orifice	2.54 mm (.100 inch)	2.54 mm (.100 inch)	2.54 mm (.100 inch)		2.54 inch (.100 inch)	4.58 mm (0.180 inch)	6.60 mm (.260 inch)
Color of the Outer Spring of the Load Piston	Light green color	Yellow color	Light green color		Light green color	Light blue color	Light green color
Color of the Inner Spring of the Load Piston	Light blue color	Light blue color	Light blue color		Orange color	Light green color	Light green color
Size of the Decay Orifice	1.40 mm (0.055 inch)	1.57 mm (0.062 inch)	1.98 mm (0.078 inch)		1.57 mm (0.062 inch)	1.40 mm (0.055 inch)
Color of the Decay Orifice	Yellow color	Green color	Red color		Green color	Yellow color

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⁽¹⁾	The location of the load piston body is identical to the location of the station for the valve. Station "H" is not used.

Selector and Pressure Control Valve

Dual Stage Relief Valve For The Pump

Maximum pressure at high idle in torque converter drive ... 3175 kPa (460 psi)

System pressure at 1300 rpm in direct drive with the lockup clutch solenoid that is energized ... 2100 ± 100 kPa (305 ± 15 psi)

Minimum pressure at low idle in torque converter drive ... 2515 kPa (365 psi)

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Table 11
Chart of Spacers for the Relief Valve
Pt. No. for the Spacers	Thickness of the Spacers	Change in Pressure as a result of one Spacer
145-0105 Spacer	.25 mm (0.010 inch)	46 kPa (6.7 psi)
145-0106 Spacer	.90 mm (0.035 inch)	166 kPa (24.1 psi)
145-0107 Spacer	1.60 mm (0.063 inch)	286 kPa (41.5 psi)

Priority Reduction Valve

Setting of the pilot pressure for the priority reduction valve ... 1755 ± 35 kPa (255 ± 5 psi)

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Table 12
Chart of Spacers for the Priority Reduction Valve
Pt. No. for the Spacers	Thickness of the Spacers	Change in Pressure as a result of the Spacers
5M-3492 Spacer	.25 mm (0.010 inch)	17 kPa (2.5 psi)
7M-1397 Spacer	.91 mm (0.036 inch)	60 kPa (8.7 psi)