For Husqvarna Parts Call 606-678-9623 or 606-561-4983
SECTION 1. DESCRIPTION AND OPERATION
INTRODUCTION
The purpose of this manual is to provide information useful in servicing the Hydro-Gear
Integrated Zero Turn (IZT) transaxle. This manual includes the IZT’s general description, hydraulic schematic, technical specifications, servicing and troubleshooting procedures.
The transaxle normally will not require servicing during the life of the vehicle in which it is installed. Should other servicing be required, the exterior of the transaxle will need to be thoroughly cleaned before beginning most procedures.
GENERAL DESCRIPTION
The 310-2400 is a self contained unit designed for the transfer and control of power. It provides an infinitely variable speed range between zero and maximum in both forward and reverse modes of operation.
This transaxle uses a variable displacement pump with a maximum displacement of 10cc per revolution, and motor with a fixed displacement of 21cc per revolution. The variable displacement pump features a cradle mounted swashplate with a direct-proportional displacement control. Reversing the direction of the swashplate reverses the flow of oil from the pump and thus reverses the direction of the motor output rotation. The pump and motor are of the axial piston design and utilize spherical nosed pistons which are held against a thrust race by internal compression springs.
The 310-2400 has a self contained fluid supply and an internal filter. The fluid is forced through the filter by a positive “head” on the fluid in the housing/expansion tank with an assist by the negative pressure created in the pump pistons as they operate.
The check valves in the center section are used to control the makeup flow of the fluid to the low pressure side of the loop.
A bypass is utilized in the 310-2400 to permit moving the vehicle for a short distance at a maximum of 2 m.p.h. (3.2 Km/h) without starting the engine.
WARNING
Actuating the bypass will result in the loss of hydrostatic braking capacity.
The machine must be stationary on a level surface and in neutral when actuating the bypass.
The 310-2400 is configured for both floating disc and cog style parking brakes.
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Figure 1. 310-2400 Hydraulic Schematic www.mymowerparts.com
310-2400 IZT
For Husqvarna Parts Call 606-678-9623 or 606-561-4983
CYLINDER
BLOCK
ASSEMBLY
INPUT
SHAFT
VARIABLE
SWASHPLATE
VARIABLE
DISPLACEMENT
10cc PUMP
CHECK VALVE
BYPASS
ACTUATOR
CYLINDER BLOCK
ASSEMBLY
FIXED
SWASHPLATE
MOTOR
SHAFT
FIXED
DISPLACEMENT
21cc MOTOR
CHECK VALVE
TRANSAXLE
HOUSING
RESERVOIR
FILTER
Figure 2. 310-2400 Hydraulic Flow Illustration
HYDRAULIC SCHEMATIC
Figure 2 provides an illustration of the hydraulic oil circuit. The oil supply for the hydraulic system of the 310-2400 IZT is also utilized for lubricating the components of the final drive assembly. designed into the product for lubrication purposes (around pistons, under the rotating cylinder blocks, etc.). This “lost” fluid returns to the transaxle housing, then is pulled back into one of the check valves depending upon the direction of vehicle operation. All of this oil must pass through an internal filter.
The input shaft and pump cylinder block are turned in one direction only by the engine/drive belt/pulley combination. Output of the oil flow is controlled by the direction and amount that the variable swashplate is angled. As the pump pistons compress they force the oil to flow through one of two passageways (forward or reverse) in the center section to the motor cylinder block and motor shaft. Since the motor has a fixed displacement angle it is forced to turn with the flow of oil. As the angle of the pump swashplate is increased the amount of oil being pumped will increase and cause a higher speed output of the motor. Reversing the angle of the swashplate will reverse the direction of oil flow.
The motor cylinder block mounts onto a splined motor shaft which drives the gear train.
The bypass feature in the 310-2400 has a mechanical lever which lifts the motor block off of the center section running surface, allowing any oil flowing from the pump block to be discharged into the housing without turning the motor.
During the operation of the transaxle, fluid is
“lost” from the hydraulic loop through leak paths
310-2400 IZT 3 www.mymowerparts.com
For Husqvarna Parts Call 606-678-9623 or 606-561-4983
EXTERNAL FEATURES 310-2400L
Back Cover
Back Cover
Axle Shaft
Disc Brake Assembly
Hub
Assembly
Fill Port
Input Shaft
Bypass
Actuator
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Cog Brake Assembly
Seal Plug
Lower Cover
Control Arm
Assembly www.mymowerparts.com
310-2400 IZT
For Husqvarna Parts Call 606-678-9623 or 606-561-4983
EXTERNAL FEATURES 310-2400R
Back Cover
Axle Shaft
Back Cover
Hub
Assembly
Bypass
Actuator Input Shaft
Fill Port
Disc Brake Assembly
310-2400 IZT
Control Arm
Assembly
Lower Cover
Seal Plug
Cog Brake Assembly
5 www.mymowerparts.com
For Husqvarna Parts Call 606-678-9623 or 606-561-4983
TECHNICAL SPECIFICATIONS
Technical specifications for the 310-2400 IZT are listed in Table 1.
Overall Transaxle Reduction
19.2:1
Input Speeds
Maximum: 3000 RPM
Minimum: 1800 RPM
Tire Diameter
18 in; 45.7cm with 325 lbs; 147.4 kg maximum weight on tires
Axle Shaft Options
Type: Keyed / Double “D”
Diameter: 0.984 inch; 25.0 mm
Type: Flanged
Diameter: Hub
Brake Type
Disc, Parking
Cog, Parking
Weight of Unit
30 lb; 14 kg
Table 1. 310-2400 Technical Specifications
PRODUCT IDENTIFICATION
The model and configuration of the 310-2400 IZT can be determined from the label shown in
Figure 3.
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Figure 3. 310-2400 Configuration Label www.mymowerparts.com
310-2400 IZT
