T2® / T2-HP™ / T3 HD™ Integrated Hydrostatic Transaxle Service and Repair Manual BLN-52749 February 2013
TABLE OF CONTENTS Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . �������1 RH Axle Shaft. . . . . . . . . . . . . . . . . . . . . . . . . . . �����24 Description and Operation . . . . . . . . . . . . . . . . . �������2 Bull Gear Set. . . . . . . . . . . . . . . . . . . . . . . . . . . . �����25 Introduction. . . . . . . . . . . . . . . . . . . . . . . . .
FOREWORD Headquartered in Sullivan, Illinois, Hydro-Gear® is a world leader in the design, manufacture, and service of quality hydrostatic transaxles for the lawn and garden industry. The mission of our company is to be recognized by our customers and the industry as a world-class supplier and the quality leader in everything we do.
DESCRIPTION AND OPERATION INTRODUCTION The purpose of this manual is to provide information useful in servicing the Hydro-Gear® T2®, T2-HPTM and T3 HDTM Integrated Hydrostatic Transaxle. This manual includes the T2, T2HP and T3 HD’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.
DESCRIPTION AND OPERATION (CONTINUED) HYDRAULIC SCHEMATIC Figure 1 is a schematic of the hydraulic oil circuit. The oil supply for the hydraulic system of the T2®, T2-HPTM and T3 HDTM is also utilized for lubricating the components of the final drive assembly. 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.
EXTERNAL FEATURES T2® / T2-HPTM / T3 HDTM Bypass Arm Control Arm Input Shaft Side Housing Main Housing LH Axle RH Axle Oil Fill Plug Expansion Tank — Top View — Input Shaft Control Arm Expansion Tank Brake Arm LH Axle RH Axle Side Housing Main Housing — Inboard View — 4 T2® / T2-HPTM / T3 HDTM
EXTERNAL FEATURES T2® / T2-HPTM / T3 HDTM Expansion Tank Bypass Arm Control Arm RH Axle — Outboard View—Left — Pulley Fan Oil Fill Plug Expansion Tank Bypass Arm Brake Arm LH Axle Brake Rotor — Outboard View—Right — T2® / T2-HPTM / T3 HDTM 5
TECHNICAL SPECIFICATIONS TECHNICAL SPECIFICATIONS T2 ® Overall Transaxle Reduction 20.63:1 T2-HP TM 22.68.1 25.42:1 T3 HD TM 24.27:1 26.70:1 29.91:1.
SAFETY This symbol points out important safety instructions which, if not followed, could endanger the personal safety and/or property of yourself and others. Read and follow all instructions in this manual before attempting maintenance on your transaxle. When you see this symbol - HEED ITS WARNING. Wear appropriate clothing. Loose or hanging clothing or jewelry can be hazardous. Use the appropriate safety equipment, such as eye and hearing protection, and safety-toe and slip-proof shoes.
TROUBLESHOOTING WARNING Do not attempt any servicing or adjustments with the engine running. Use extreme caution while inspecting the drive belt assembly and all vehicle linkage! Follow all safety procedures outlined in the vehicle owner’s manual. In many cases, problems with the T2®, T2-HPTM and T3 HDTM are not related to a defective transaxle, but are caused by slipping drive belts, partially engaged bypass valves, and loose or damaged control linkages.
SERVICE AND MAINTENANCE NOTE: Any servicing dealer attempting a warranty repair must have prior approval before conducting maintenance of a Hydro-Gear® product unless the servicing dealer is a current Authorized Hydro-Gear Service Center. EXTERNAL MAINTENANCE Regular external maintenance of the T2®, T2HPTM and T3 HDTM should include the following: 1. Check the vehicle operator’s manual for the recommended load ratings. Insure the current application does not exceed load rating. 2.
FLUID CHANGE PROCEDURE This transaxle is factory filled, sealed and does not require oil maintenance. However, in the event of oil contamination or degradation, oil addition or change may alleviate certain performance problems. 1. Remove the transaxle from the vehicle. 2. Clean the expansion tank and oil fill port areas of any debris. 3. Remove the oil fill port fitting. 4. Position the transaxle so the oil will drain completely out of the housing. 5.
PURGING PROCEDURES Due to the effects air has on efficiency in hydrostatic drive applications, it is critical that it be purged from the system. These purge procedures should be implemented any time a hydrostatic system has been opened to facilitate maintenance or any additional oil has been added to the system. Air creates inefficiency because its compression and expansion rate is higher than that of the oil approved for use in hydrostatic drive systems.
RETURN TO NEUTRAL SETTING WARNING WARNING POTENTIAL FOR SERIOUS INJURY Certain procedures require the vehicle engine to be operated and the vehicle to be raised off the ground. To prevent possible injury to the servicing technician and/or bystanders, insure the vehicle is properly secured. The return to neutral mechanism on the transaxle is designed to set the directional control into a neutral position when the operator removes their foot from the foot control.
BRAKE MAINTENANCE BRAKE SETTING FRICTION PACK ADJUSTMENT 1. Remove the brake arm bias spring(134), and then the cotter pin (133) securing the brake castle nut (132). The friction pack dampens or holds the operator control lever in its desired position. 2. Insert a 0.020” feeler gage between the brake rotor (121) and top brake puck, and then set the brake by finger tightening or loosening the castle nut. 3. Install a new cotter pin to secure the castle nut, and then install the brake arm bias spring.
TEAR DOWN AND REASSEMBLY HOW TO USE THIS MANUAL Each subassembly illustrated in this section is illustrated by an exploded view showing the parts involved. The item reference numbers in each illustration are for assembly instructions only. See pages 37 and 39 for part names and descriptions. A complete exploded view and item list of the transaxles is provided on pages 36 and 39. Many of the parts and subassemblies of these transaxles can be removed and serviced independently of other components.
TOOLS Miscellaneous R E QUIRED TOOL S Flat Blade Screw Driver (2) Torque Wrench Air Impact Wrench Rubber or Neoprene Mallet Breaker Bar Side Cutters/Snips Needle Nose Pliers Large External Snap Ring Pliers Small Internal Snap Ring Pliers 1/2”-3/8” Adapter 1/2” Deep 7/16” Deep 3/4” Deep 7/8” Deep 9/16” Deep T-40 Torx Head 10 mm Sockets TORQUES Item Description R E Q U I R ED TORQUE VAL UES Torque Operation 8 HFHCS 1/4-20 x 1.25 105-155 in-lbs [11.8-17.
TRANSAXLE REMOVAL NOTE: It is necessary to remove the T2®, T2HPTM or T3 HDTM from the vehicle before performing the repair procedures presented in this section. Before starting any disassembly, make certain that your work area is neat and clean. Clean the external parts of the transaxle. The following procedures are presented in the order recommended for a complete tear down of the transaxle. Do not disassemble the unit any farther than necessary to accomplish the required repairs.
FAN AND PULLEY Refer to Figure 8 Refer to Figure 9 PULLEY AND FAN CONFIGURATION HUB, FAN AND PULLEY CONFIGURATION 1. Remove the locknut (152). 1. Remove the locknut (152). 2. Remove the washer (153) if applicable. 2. Remove the washer (153) if applicable. 3. If applicable separate the assembly by removing the screws (153), fan (150) and the pulley (151). 3. Remove the fan (150) and the pulley (151) Inspection 1. Check all components for wear or damage. Replace if necessary. Assembly 1.
EXPANSION TANK Refer to Figure 10 Disassembly Inspection 1. Remove all items previously discussed in their recommended order. 1. Inspect all parts for wear or damage. Replace if necessary. 2. Remove the ratchet fastener (147) and discard. Assembly 1. Reassemble all parts in the reverse order of disassembly. 3. Detach the tube (145) from the tank fitting (146). The fitting (146) does not need to be removed – unless, replacing. 2.
CONTROL ARM ASSEMBLY Refer to Figure 11 Disassembly Assembly 1. Remove all items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. If opening the housing or replacing seals, remove the oil port plug (13), then; drain oil from transaxle. 2. When tightening the fasteners, refer to the table on page 15 for the required torque values. 3.
RETURN TO NEUTRAL ASSEMBLY OPTION Refer to Figure 12 Disassembly Inspection 1. Remove all items previously discussed in their recommended order. 1. Inspect all parts for wear or damage. Replace if necessary. 2. Remove the spring (167). Assembly 3. Remove the Torx head screw (41) and discard. 1. Reassemble all parts in the reverse order of disassembly. 4. Remove the scissor arm (164), and the RTN control arm (161). 2.
RETURN TO NEUTRAL/ROS ASSEMBLY OPTION Refer to Figure 13 Disassembly 3. Install the control arm (160). 1. Remove all items previously discussed in their recommended order. 4. Install the RTN scissor arm (164), washer (163) and Torx head screw (41). Refer to torque chart on page 15. 2. Remove the spring (167). 3. Remove the Torx head screw (41), discard, and the washer (163). 5. Install the switch retainer over the neutral arm tab. Place the rivet through the switch retainer and neutral arm. 4.
BRAKE ARM & BRAKE ASSEMBLY Refer to Figure 14 Disassembly 1. Remove all items previously discussed in their recommended order. 2. Remove the cotter pin (133) and discard. Mark the orientation of the bias spring (134), and long screw (127). Remove the brake arm spring (134), the castle nut (132), and the washer (131). 3. Remove the brake arm (130), and the brake compression spring (129). 4. Remove the bolt (128), the bolt (127), and the spacer (126). 5.
SIDE HOUSING Refer to Figure 15 Disassembly Assembly 1. Remove all external items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the screws (8), separate side housing (2) from main housing (1). 2. Apply a bead of sealant around the perimeter of the main housing face. See “Sealant Application Diagram” on page 34. Inspection 1. Inspect the bearing and bushing areas in the side cover for wear or damage. Replace if necessary.
RH AXLE SHAFT Refer to Figure 16 Disassembly Assembly 1. Remove all items previously discussed, in their recommended order. 1. Assemble items in reverse order of disassembly. 2. Remove the retaining ring (109)* and discard. NOTE: To protect the lip seal from possible damage when installing into the bore and over the axle shaft, apply a protective covering over the splines, sharp corners and/or keyway of the axle shaft (e.g., cellophane, tape, etc.). Remove protective covering after installation.
BULL GEAR SET Refer to Figure 17 Disassembly Assembly 1. Remove all external items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the bull gear set — two miter gears (102) with two differential pins (108), and bull gear (107). 2. Install the bull gear (107). 3. Install the miter gears (102) with the differential pins (108). Inspection 1. Inspect all items of the bull gear set for wear or damage.
REDUCTION GEAR SET Refer to Figure 18 Disassembly Assembly Reduction Gear Set: 1. Reassemble all parts in the reverse order of disassembly. 1. Remove all external items previously discussed in their recommended order. 2. Remove the washer (93), jack shaft gear (91) and reduction gear (90). 3. Remove the jack shaft (92) and second washer (93). Inspection 2. Install the washer (93) and jack shaft (92). 3. Install the jack shaft gear (91) into the reduction gear (90).
INPUT SHAFT Refer to Figure 19 Disassembly Assembly 1. Remove all external items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the retaining ring (66) and discard. 2. Install the bearing (62), a new retaining wire (63), and spring (67) onto the input shaft. 3. Remove the lip seal (65) and discard. NOTE: Apply a light coating of grease to new seal (65) before installing. Refer to “Seal Kit” in the Items List on page 37.
SWASHPLATE Refer to Figures 20-21 Disassembly Assembly 1. Requires removal of all items beginning on page 17. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the swashplate (40) and pump cylinder block assembly (70) as a single item. 2. Apply a light coating of oil to running surfaces on center section, swashplate bearing races, thrust bearing assembly and pump block assembly.
BYPASS ARM Refer to Figure 22 Disassembly Assembly 1. Remove all external items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the retaining ring (35) and discard. Remove the bypass arm (34). 2. Install a new lip seal (30). 3. Remove the retaining ring (33) and discard. 4. Remove the bypass rod (32) and the clip retaining ring (31) as a single item.
CENTER SECTION, MOTOR SHAFT & MOTOR BLOCK Refer to Figure 23 Disassembly Assembly 1. Requires removal of all items beginning on page 17. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the center section mounting screws (22). 2. Apply a light coating of oil to all running surfaces. 3. Remove the center section, the motor shaft (82) and the bypass plate (23). 3. Place the thrust bearing assembly (79) into the main housing.
FILTER ASSEMBLY CYLINDER BLOCKS Refer to Figure 24 Refer to Figure 25 Disassembly Inspect each component of the cylinder block assemblies for wear or damage. Inspect the cylinder blocks’ running surface for scratches. Replace if necessary. 1. Remove the magnet (28) and the filter (27). The filter can be removed without damaging the filter base (26). 2. Remove the deflector (29). 3. Inspect the check plugs (24, 25). Remove if necessary. NOTE: Mark plugs before removal. 4. Inspect the filter base (26).
LH AXLE SHAFT Refer to Figure 26 Disassembly Assembly 1. Remove all items previously discussed, in their recommended order. 1. Assemble items in reverse order of disassembly. 2. Remove the retaining ring (109)* and discard. NOTE: To protect the lip seal from possible damage when installing into the bore and over the axle shaft, apply a protective covering over the splines, sharp corners and/or keyway of the axle shaft (e.g., cellophane, tape, etc.). Remove protective covering after installation.
EXPANSION TANK HOSE AND FITTING Refer to Figure 27 Disassembly Assembly 1. Remove the expansion tank hose (141). 1. Install the fitting into the main housing. Refer to torque chart on page 15. 2. Remove the O-ring (142) from the expansion tank fitting (140) and discard. 3. Remove the expansion tank fitting (140). Inspection 2. Install a new O-ring (142) onto the fitting. 3. Place the expansion tank hose (141) onto the fitting (140). 1. Inspect the fitting for damage and replace if necessary.
ASSEMBLY AFTER A COMPLETE TEAR DOWN If the unit has been torn down completely, the following summary identifies the assembly procedures necessary to completely assemble the unit. Each assembly procedure is located by a page reference. The part reference numbers provided in each assembly procedure are keyed to the individual procedure illustrations, and are also keyed to the complete unit exploded views on pages 36 and 38. 1. Install the expansion tank hose and fitting. See page 33. 2.
SIDE HOUSING – SCREW TIGHTENING SEQUENCE Starting with the number “1” screw location, tighten sequentially through to “10.” Torque each screw to 105 – 155 lb-in (11.8 – 17.5 Nm). NOTE: As a general rule, use the low end of the torque specification.
T2® / T2-HPTM TRANSAXLE EXPLODED VIEW 36 T2® / T2-HPTM / T3 HDTM
T2® / T2-HPTM TRANSAXLE PARTS LIST 1 2 7 8 10 11 13 20 22 23 24 25 26 27 28 29 30 31 32 33 34 35 40 41 42 43 44 45 46 47 48 49 61 62 63 64 65 66 67 70 74 75 79 80 81 82 83 90 91 92 93 100 Housing, Main Housing, Side Seal, Lip (included in Center Section Kit 202) HFHCS 1/4-20 x 1.25 Sealant, Loctite 5900 Oil, 20W50 Plug Center Section Bolt, Hex Flange Plate, Bypass Check Plug Assembly w/Washer Check Plug/w Assembly w/Washer, .
T3 HDTM TRANSAXLE EXPLODED VIEW 38 T2® / T2-HPTM / T3 HDTM
T3 HDTM TRANSAXLE PARTS LIST 1 2 7 8 10 11 13 30 31 32 33 34 35 40 41 61 64 65 66 70 74 75 79 80 81 82 83 90 91 92 93 100 101 102 103 Housing, Main Housing, Side Seal, Lip (included in Center Section Kit 202) HFHCS 1/4-20 x 1.25 Sealant, Loctite 5900 Oil, 20W50 Kit, Fitting Seal, Lip (included in Center Section Kit 202) Ring, Retaining (included in Center Section Kit 202) Rod, Actuator Ring, Retaining (included in Center Section Kit 202) Arm, Bypass Ring, Retaining Trunnion, Swashplate TWHCS 5/16-18 x 1.
GLOSSARY OF TERMS Axial Piston: Type of design for hydraulic motors and pumps in which the pistons are arranged parallel with the spindle (input or output shaft). Bypass Valve: A valve whose primary function is to open a path for the fluid to bypass the motor or pump. Also referred to occasionally as the freewheel valve or dump valve. Case Drain Line (Return Line): A line returning fluid from the component housing to the reservoir.
Integrated Zero-Turn Transaxle: The combination of a hydrostatic transmission and gear case in one housing to form a complete transaxle. Manifold: A conductor which provides multiple connection ports. Neutral: Typically described as a condition in which fluid flow and system pressure is below that which is required to turn the output shaft of the motor. Pressure Decay: A falling pressure.
© 2010 HYDRO-GEAR Printed in U.S.A. Rev.
