CX31-P600 Petroleum Transmission Transmission Cooling System Caterpillar

Transmission Cooling (General Recommendations)

Automatic transmissions generate heat due to converter slippage, charging pump losses, and friction in rotating components. The transmission fluid absorbs this heat, and an oil cooler is required to dissipate it. Keeping the oil cool maintains the oil's lubricating properties, allows the transmission to perform properly, and extends the life of the transmission components.

The engine coolant (antifreeze) and the transmission fluid (TDTO) absorb the heat generated by the engine and transmission. The two fluids carry the heat to a heat exchanger (radiator or cooler) so that the oil or antifreeze can be cooled.

See the Transmission Application and Installation Guide, Engine Application and Installation Guide, and refer to Special Publication, SEBU6250, "AVSpare Machine Fluid Recommendations" for specific transmission drive train oil and engine fluid requirements.

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Converter Cooling

AVSpare Petroleum Transmissions have lockup clutches that reduce the heat generated by converters in all gears except first gear and reverse. Under normal operating conditions, the transmission will upshift and downshift to the proper gear ratio and spend most the operating time in the converter lockup clutch mode. The lockup clutch reduces the converter cooling requirements. If the driver selects first gear hold, the lockup clutch is disabled. This mode of operation will result in continuous converter usage so that converter slippage will generate higher heat loads. The application, ambient temperatures, horsepower being transmitted, and the length of time in converter drive will dictate transmission cooling requirements.

Temperature Operating Limits

The maximum allowable transmission oil temperatures for normal (continuous) and intermittent conditions are the following:

Continuous sump ... 90 °C (194 °F)

Continuous converter out ... 99 °C (210 °F)

Intermittent sump ... 99 °C (210 °F)

Intermittent converter out ... 121 °C (250 °F)

Oil Temperature Gauges

If the OEM chooses to use a transmission/converter color coded converter outlet temperature gauge, the following requirements and recommendations apply:

Green - Safe zone is below 99 °C (210 °F)

Yellow - Caution zone is 99 °C (210 °F) to 121 °C (250 °F)

The following requirement applies:

Red - Warning above 121 °C (250 °F)

If the OEM chooses to use a transmission color coded sump temperature gauge, the following recommendations and requirements apply:

Green - Safe below 90 °C (194 °F)

Yellow - Caution between 90 °C (194 °F) and 99 °C (210 °F)

The following requirement applies:

Red - Warning zone above 99 °C (210 °F)

Transmission Overheating

In the unlikely event that the transmission does over heat, the transmission should be shifted to neutral and engine speed should be elevated to high idle until the transmission temperature returns to the proper operating temperature. Elevating the engine speed to high idle causes the engine fan to provide the most air to flow across the radiator, which maximizes oil flow through the cooler.

Towing/Coasting

Since the transmission hydraulic pump is engine driven, it varies with engine speed. One of the many functions of this pump is to provide lubrication. If the engine speed is non-existent (towing) or at a lower level than intended (coasting), considerations must be taken into account. If the CX31-P600 is installed in a wheeled vehicle that requires towing, the drive shaft must be disconnected from the transmission or the drive axle(s) lifted off the ground. Coasting in NEUTRAL position is not recommended by AVSpare, but if a coasting in neutral situation should occur, engine speed must be elevated to provide proper lubrication to the transmission.

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POWER TAKE OFF (PTO)

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The CX31-P600 transmission is available in integral drive and straight through configurations. The integral drive CX31-P600 configuration features direct drive pump PTO's located on top of the converter housing with SAE "B" and "C" pump mounting pads and an optional direct drive pump rear power take-off (RPTO) adjacent to the transmission output shaft for non-drop box configurations. The straight through CX31-P600 configuration features two PTO mounting pads on the sides of the converter housing and an optional direct drive pump rear power take-off (RPTO) adjacent to the transmission output shaft for straight through configurations. As viewed from the rear, side PTO positions are at 8 o'clock and 1 o'clock. Bolt on PTO units for use with the side PTO position on the straight through CX31-P600 configuration are available from aftermarket suppliers and can be specified to adapt to a variety of output options. Specifying and designing the installation of the side PTO devices is the responsibility of the OEM, body builder, or the end user.

Side PTO's turn at engine speed (1:1) and rotate the same direction as the transmission input. Integral drive PTO's turn faster than the engine (1.09:1). Integral drive PTO SAE "C" mounting pads rotate in the same direction as the transmission input. Integral drive PTO SAE "B" mounting pads rotate in the opposite direction of the transmission input. The RPTO turns faster than the engine at 1.25:1 and in the opposite direction as the transmission input. The maximum rated torque/power for the PTO locations is listed in Table 1.

PTO Torque Limits

All CX31-P600 transmissions are capable of driving either two side PTOs or as many as four PTOs from an integral drive on top of the torque converter housing. The CX31-P600 can be factory ordered with an optional rear PTO, which also may be installed in the field if necessary. Bolt on PTO units are available from aftermarket suppliers and can be specified to adapt to a variety of output options. Specifying and designing and installing the PTO devices are the responsibility of the OEM, body builders and the end user.

The maximum torque allowed at the transmission PTO pads at any engine speed is listed in Table 1. The maximum power allowed at the transmission PTO pads is speed dependent. Horsepower can be calculated by multiplying torque in lb ft times rpm and dividing by 5252. The power and speed limitations will most likely be restricted by the aftermarket PTO and pumps selected, and not by the transmission capability.

When PTOs and pumps are mounted on a AVSpare transmission, it creates a bending moment that puts stress on the transmission case. It is the OEMs responsibility to ensure that the PTOs and pumps are supported in a manner that prevents overloading of the transmission case. Bending moments are measured from the centerline of the PTO mounting pad and include PTO, direct mount pump, and any unsupported hydraulic lines. Bending moment limits are listed in Table 2.

Any further inquiries concerning PTOs and pump design should be directed to the AVSpare Transmission Business Unit through the Application Support Center. The web site for the Application Support Center is http://applicationsupport.cat.com.

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To avoid personal injury due to entanglement with rotating shaft, keep PTO master cover and all power drive system covers in place. Install PTO shaft guard when the system is not in use.

Note: Serious injury can be prevented with proper drive shaft guards. It is the OEM or the auxiliary PTO installer's responsibility to provide guards on exposed rotating parts.

Transmission PTO Control

The CX31-P600 Transmission ECU may be used to program PTO functions or the PTO supplier may provide separate PTO controls. The programmable features may include, but are not limited to the following:

• PTO operation in Neutral only

• PTO engagement below a specific engine speed

• PTO overspeed protection

Side PTO Bolt Requirements

• M10 x 1.5 externally threaded fastener

• Minimum fastener Grade 10.9 in accordance with SAE J1199 (1040 mPa min)

• The minimum quantity of 8 bolts are required to secure the PTO to the transmission. Alignment dowels are optional hardware that may be provided by the PTO supplier.

Side PTO Sealing Requirements

• The side mounted PTO shall be sealed to the transmission with a rubber coated metal interface gasket (RCM).

• Do not use sealing compounds. The compounds are usually incompatible with transmission drive train oil (TDTO).

• The RCM gasket supplied by the PTO manufacturer will have the appropriate thickness and tolerance to maintain the required gear center distance. Shimming this PTO is not required.

• The PTO gasket used to seal the PTO cover is intended to be discarded when installing a side PTO.

• Paper gaskets shall not be used to seal the PTO to the transmission.

Rear PTO Interface

Removal of the rear PTO cover after the transmission has been properly filled with oil may cause the loss of some fluid. The amount of oil that is lost will depend on the installation angle of the transmission and the surface plane of the vehicle when the cover is removed. (Some PTO component suppliers recommend draining the transmission oil prior to installation of PTO components). Check the transmission oil level after installation of PTO components to ensure that any oil lost has been replaced and that the added component did not increase the oil requirements of the transmission. The installation dimensional drawings provide additional specifications for the rear PTO mounting pad.

Note: Rear PTO will accept a 4 bolt SAE J744 “B” pump drive and pilot. A supplier adapter is required to mate with the 17 tooth AVSpare spline.

Rear PTO Bolt Requirements

• M12 x 1.75 externally threaded fastener.

• Minimum fastener Grade 10.9 in accordance with SAE J1199 (1040 mPa min)

• A minimum quantity of 8 bolts is required in order to secure the PTO to the transmission.

Rear PTO Sealing Requirements

• The rear PTO is designed for a standard 241, 2H-3934 O-Ring Seal

• The O-ring is intended to provide a static radial seal over the pilot diameter of the unit mating to the rear PTO pad.

• O-ring Seal material, NBR (Nitrile).

Integral Pump Drive Bolt Requirements

• Two M16 X 2 externally threaded fastener.

• Four M12 X 1.75 externally threaded fastener.

• Minimum Fastener Grade 10.9 in accordance with SAE J1199 (1040 MPa min)

• Two and Four bolt pump pads. Use all bolt locations available on the selected pump pad.

Integral Pump Drive Sealing Requirements

• The SAE "B" pads are designed for a standard 243, 4M-0189 O-Ring Seal

• The SAE "C" pads are designed for a standard 250, 5F-3106 O-Ring Seal.

• The O-ring is intended to provide a static radial seal over the pilot diameter of the unit mating to the PTO pad.

• O-ring Seal material, NBR (Nitrile).

PTO Electrical Connections

• The CX31-P600 may be ordered with an optional variable pump displacement control capability. Refer to Special Instruction, REHS3514, "Application and Installation Guide (Electrical)" for specific OEM electric interface definitions and for the requirement.

• Refer to the supplier of the PTO attachment for installation instructions of the PTO electrical connections.

Illustration 1	g03438721
PTO control oil supply (1) Ports

PTO Control Oil Supply

Two ports shown in Illustration 3 are provided for PTO control (clutch) oil supply purposes. Transmission Drive Train Oil (TDTO) used for PTO control is supplied at approximately 2137 kPa (310 psi). Both ports are SAE #4 J1926 (7/16 -20 O-ring face seal) ports.

DIRECTION OF ROTATION

Engine Rotation SAE J824 (standard)

• Counterclockwise as viewed from the flywheel end of the engine

Transmission Output Rotation

• Forward Same as Input

• Reverse Opposite of Input

PTO Rotation

• Side PTO drive gear rotates at engine rpm and in the same direction as the transmission input.

• Rear PTO shaft rotates at 1.25 X Engine rpm and in the opposite direction of the transmission input.

• Integral Drive PTO SAE "C" mounting pad rotates at 1.09 X Engine rpm and in the same direction as the transmission input.

• Integral Drive PTO SAE "B" mounting pad rotates at 1.09 X Engine rpm. Due to the location of the mounting pad, pumps should be specified that turn opposite of the transmission input.

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LOAVSIONS OF SUPPORT BRACKETS

Note: The following illustrations are typical examples of the locations that are used for the support brackets.

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Illustration 2	g03438876
CX31–P600 Petroleum Transmission With Integral Pump Drives (2) Bolt locations for support bracket

Illustration 3	g03439120
CX31–P600 Petroleum Transmission With Integral Pump Drives (2) Bolt locations for support bracket

Illustration 4	g03439216
CX31–P600 Petroleum Transmission With Two-Wheel Drive Drop Box (2) Bolt locations for support bracket

Illustration 5	g01909883
CX31–P600 Petroleum Transmission With Two-Wheel Drive Drop Box (2) Bolt locations for support bracket

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BOLT TORQUES

Standard torque values are listed in Tables 4 and 5 below. Non standard (special) torque values are called out in the specifications section of Specifications, System Operation, Testing and Adjusting, KENR6986. The specifications section takes precedence over the standard torque values listed in the tables below.

Standard Bolt Torques