ZT-2800®/ZT-3100®/ZT-3200™/ZT-3400® Integrated Zero-Turn Transaxle Service and Repair Manual BLN-52441 February 2021
Table Of Contents Foreword...................................................... � 1 Tear Down and Reassembly........................21 Product Identification.................................... � 1 How To Use This Manual.............................21 Description and Operation............................ � 2 General Instructions..................................... 21 Introduction................................................... � 2 Tools............................................................
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® ZT-2800®, ZT-3100®, ZT-3200TM and ZT-3400® Integrated Zero-Turn Transaxles. This manual includes the general descriptions, hydraulic schematics, technical specifications, servicing and troubleshooting procedures for both transaxles.
HYDRAULIC SCHEMATIC Vent Input Shaft Case Reservoir Bypass Motor Pump Motor Shaft System Check Valves Filter Charge Relief Charge Pump Figure 2, Hydraulic Schematic With Charge Pump Vent Input Shaft Pump Case Reservoir Bypass Motor Motor Shaft System Check Valves Filter Figure 3, Hydraulic Schematic Without Charge Pump (ZT-2800) ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400® 3
EXTERNAL FEATURES ZT-2800®/ZT-3100®/ZT-3200TM (ZT-3400® similar) Axle Shaft Main Housing Bypass Arm Control Arm Drain Port (For Horizontal Installation) — Top View — Top Port Plug Parking Brake Arm Side Cover — Inboard View — 4 ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400®
EXTERNAL FEATURES ZT-2800®/ZT-3100®/ZT-3200TM (ZT-3400® similar) Input Shaft Axle Shaft Oil Filter Expansion Port (For Horizontal Installation) — Outboard View—Left (Standard Control) — Fan and Pulley Kit Return To Neutral Assembly Charge Pump — Outboard View—Right (Return To Neutral Control) — ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400® 5
TECHNICAL SPECIFICATIONS SPECIFICATIONS Overall Transaxle Reductions Pump Displacement Motor Displacement Filter Rating ZT-2800 ® ZH/ZJ ZK/ZL ZM 20.69:1 24.74:1 27.23:1 ZT-3100 ® ZJ ZL ZM 20.69:1 24.74:1 ZT-3200 TM ZM 27.23:1 27.23:1 0.61 in3/rev [10cc/rev] 0.
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 a transaxle 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 External Maintenance Regular external maintenance of the transaxle should include the following: Fluids 1. Check the vehicle operator’s manual for the recommended load ratings. Insure that the current application does not exceed load rating. been carefully selected, and only equivalent, or better products should be substituted. 2. Check oil level in accordance with “Fluid Change Procedure,” step 12. Refer to page 11. 3.
FILTER AND FILTER GUARD Refer to Figure 4 Disassembly Assembly 1. Remove the hex head screws (105), and filter guard (106). 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the filter (23) and discard. The recommended tool for removal is the socket-style wrench. The strap or band style wrenches have the potential to twist the filter canister if the filter seal has tightened due to expansion and contraction over time. 2.
FLUID CHANGE PROCEDURE This transaxle is designed with an external filter for ease of maintenance. To ensure constant fluid quality levels and longer life, an initial oil and filter change at 75-100 hours, then every 400 hours thereafter is recommended. The following procedure can be performed with the transaxles installed in the vehicle, and the vehicle on level ground. Apply the bypass valve for each transaxle and lock the vehicle parking brake. 1.
PURGING PROCEDURES Due to the effects air has on efficiency in hydrostatic drive applications, it is critical that it is purged from 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. The following procedures are best performed with the vehicle drive wheels off the ground. Then repeated under normal operating conditions.
RETURN TO NEUTRAL SETTING WARNING WARNING POTENTIAL FOR SERIOUS INJURY Do not attempt any servicing or adjustments with the engine running. Use extreme caution while inspecting the drive belt assembly and all vehicle linkage! Inattention to proper safety, operation, or maintenance procedures could result in personal injury, or damage to the equipment. Before servicing or repairing the transaxle, fully read and understand the safety precautions described in this section.
RETURN TO NEUTRAL ASSEMBLY Refer to Figure 8 Disassembly Assembly 1. Remove all items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the RTN control arm kit (211) by first removing the spring (147) and Torx head screw (46), discard the screw. The remaining members of the assembly can be removed as a single item – washer (146), unidirectional scissor arm kit (145), and the control arm (44). 2.
CONTROL ARM ASSEMBLY Refer to Figure 9 Disassembly Assembly 1. Remove all items previously discussed in their recommended order. 1. Reassemble all parts in the reverse order of disassembly with the exception of the washer (45) and the lock nut (47). 2. Remove the lock nut (47), and the washer (45). Discard both items. 3. Remove the Torx head screw (46). NOTE: Discard the washer (45) and the lock nut (47). 4. Remove the control arm (44), the washer (43) and the stud (42). 2.
ZT-2800®/ZT-3100® PARKING BRAKE ADJUSTMENT (Code 1 or 2) Only if Character #7 in the model number code is 1 or 2. Example: ZX-XXXX-1XXX-XXXX WARNING POTENTIAL FOR SERIOUS INJURY When servicing the parking brake on unlevel terrain, it is essential to chock the vehicle wheels to prevent vehicle movement. It should not be necessary to adjust the transaxle parking brake over the life of the vehicle.
ZT-2800®/ZT-3100® PARKING BRAKE ASSEMBLY (Code 1 or 2) Only if character #7 in the model number code is 1 or 2. Example: ZX-XXXX-1XXX-XXXX Refer to Figure 12 Disassembly Inspection 1. Mark the position of the cam stop retainer (104) in relation to the side cover (2). 1. Inspect all parts for excessive wear or damage. Replace if necessary. NOTE: The orientation of the cam stop and brake-cam to one another is very important.
ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400® BRAKE ARM ASSEMBLY (Code 3/5/6/7) Character #7 in the model number code is 3, 5, 6 or 7. Example: ZX-XXXX-3XXX-XXXX Refer to Figure 13 Disassembly Inspection 1. Mark the position of the brake arm (102) in relation to the brake shaft (101). 1. Inspect all parts for excessive wear or damage. Replace if necessary. NOTE: The orientation of the brake arm and brake shaft to one another is very important. 2. Inspect the splines on the brake arm and brake shaft. 2.
ZT-2800®/ZT-3100® PARKING BRAKE ASSEMBLY Assembly (Code A) Example: ZX-XXXX-AXXX-XXXX Refer to Figure 14 1. Reassemble all parts in the reverse order of disassembly. See page 22 for the torque values of the brake yoke bolts (176 and 175). Disassembly Brake Setting 1. Remove the brake arm bias spring (185). Note the orientation of the spring for proper reassembly. 1. Remove the brake arm bias spring (185) and the cotter pin (182) securing the castle nut (181). Discard the cotter pin. 2.
HUB REMOVAL Do not use this procedure to remove the drive wheel from the transaxle. Remove the drive wheel by removing the lug nuts. 4. Insert the hub removal tool over the flange wheel hub studs. Install lug nuts and secure evenly. Torque to 100 lb-in. (11.3 Nm). DESCRIPTION: Follow the directions below for removal of flanged hubs from tapered axle shafts to facilitate maintenance to bearings, bushings and seals externally. 5. Tighten the 1-1/8” socket head center bolt evenly and slowly.
TEAR DOWN AND REASSEMBLY How to Use This Manual Each subassembly illustrated in this manual is illustrated with an exploded view showing the parts involved. The item reference numbers in each illustration are for assembly instructions only. See pages 42-45 for part names and descriptions. A complete exploded view and item list of the transaxle is provided at the end of the repair section. General Instructions Cleanliness is a primary means of assuring satisfactory life on repaired units.
TOOLS Miscellaneous R E QUIRED TOOL S Hub Puller 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 3/8” Deep 1-1/8” Deep 1/4” Allen 3/4” Deep 9/16” Deep T-40 Torx Head 7/8” Deep Sockets TORQUES Item Description 5 7 11 23 24 25 27 42 46 99 105 111 122 123 134 142 142 162 175 176 R E Q U I R E D TORQUE VAL UES Plug 9/16-18 (Metal) Screw,
TRANSAXLE REMOVAL FAN AND PULLEY NOTE: It is necessary to remove the transaxle from the vehicle before performing the repair procedures presented in this section. To remove the wheel from the hub, do so by removing the lug nuts. Do not remove the axle/hub nut unless replacing the hub, the axle seal or removing the axle shaft. Refer to Figure 16 Before starting any disassembly, make certain that your work area is neat and clean. Clean the external parts of the transaxle.
FAN AND PULLEY (Continued) Refer to Figure 17 Refer to Figure 18 FAN AND PULLEY KIT (207) CONFIGURATION “B” FAN AND PULLEY KIT (207) CONFIGURATION “C” 1. Remove the locknut (122), and detach the fan and pulley assembly from the input shaft. 1. Remove the locknut (122) and detach the fan and pulley assembly from the input shaft. 2. Separate the assembly by removing the screws (123), fan (120) and the pulley (121). 2. Remove the hex head screws (123) to separate the fan (120) and pulley (121) assembly.
FAN AND PULLEY (Continued) Refer to Figure 19 Disassembly FAN AND PULLEY KIT (207) CONFIGURATION “D” (ZT-2800®/ZT-3100®) 1. Remove the locknut (122), slotted washer (123), pulley (121), fan (120) and pulley disc (121) the from the input shaft. Inspection 1. Check all components for excessive wear or damage. Replace if necessary. 2. Inspect input shaft splines for wear or damage. Assembly 1. Reassemble all parts in the reverse order of disassembly. 2.
SIDE COVER Refer to Figure 20 Disassembly Inspection 1. Remove all external items previously discussed in their recommended order. 1. Inspect the bearing and bushing areas in the side cover for excessive wear or damage. Replace if necessary. 2. Remove filter (23) and discard. Drain oil from transaxle. Refer to page 11. Assembly 3. Remove the screws (7), separate side cover (2) from main housing (1), using “pry points” as required. 1.
BULL, PINION AND REDUCTION GEARS Refer to Figure 21 Disassembly Assembly 1. Remove external items beginning on page 14. 1. Install the washer (74), pinion gear (72), and secure their placement with retaining ring (71) onto the motor shaft (73). 2. Remove washer (80) and reduction gear set (81-82) as an assembly and set aside. Remove second washer (80) and jack shaft pin (83). 3. Remove the washer (70), retaining ring (71), pinion gear (72) and washer (74) from the motor shaft (73). 4.
CHARGE PUMP Refer to Figures 22-22a Disassembly 1. Mark the orientation of the charge pump cover relative to the main housing, prior to removal. Refer to figure 21. 2. Remove the hex head screws (134), charge pump cover (133), gerotor assembly (131), and the O-ring (132). Remove the connecting tubes (130) and lip seal (157) at this point – only if the center section will be removed. A pick type tool can be used to remove the connection tubes and seal. 3.
CHARGE PUMP ORIENTATION Z*-L***-****-**** Z*-K***-****-**** Z*-P***-****-**** Z*-N***-****-**** Z*-G***-****-**** Z*-H***-****-**** Figure 23, Charge Pump Orientation ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400® 29
INPUT SHAFT Refer to Figure 24 Disassembly should be taken not to damage the shaft or gerotor running surface. 1. Requires removal of all items beginning on page 14. 2. Remove the retaining ring (57). Remove the bearing from pump shaft only if worn or damaged. 3. Remove the lip seal (56) and discard. 5. Remove the wire ring retainer (54) and the bearing (53) from the pump shaft (52). 4. Remove the washer (55) and the pump shaft assembly (52–54). Inspection 5.
BYPASS ARM Refer to Figure 25 Disassembly Assembly 1. Requires removal of all items beginning on page 14. 1. Install a new lip seal (30). 2. Remove the push-on retaining ring (35) and discard. Remove the bypass arm (34). 3. Remove the retaining ring (33). 4. Remove the bypass rod (32) and the clip retaining ring (31) as a single item. 2. Install the clip retaining ring (31) and bypass rod (32). 3. Install the retaining ring (33). 4. Install the bypass arm (34) and new push-on retaining ring (35).
SWASHPLATE Refer to Figures 26-27 Disassembly Assembly 1. Requires removal of all items beginning on page 14. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the swashplate (40) and pump cylinder block assembly (69) 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. 3.
CENTER SECTION Refer to Figure 28 Disassembly Assembly 1. Requires removal of all items beginning on page 14. 1. Reassemble all parts in the reverse order of disassembly. 2. Remove the center section mounting screws (27). 2. Apply a light coating of oil to all running surfaces on the center section. 3. Remove the center section, the motor shaft (73), the motor cylinder block assembly (64) and the brake shaft (101) as a single item. 3. Place the thrust bearing assembly (60) into the main housing (1).
BRAKE ASSEMBLY (Code 1 or 2) (ZT-2800®/ZT-3100®) Character #7 in the model number code = 1 or 2. Assembly Example: ZX-XXXX-1XXX-XXXX 1. Install the new O-rings (10) onto the brake (cam) shaft (101). Refer to Figure 29 NOTE: Apply a thin coating of oil to the O-rings before installing. Disassembly 1. Remove the center section per detail on page 31. NOTE: Take note of the orientation of the brake cam (101) and the brake puck (100). 2. Remove the brake (cam) shaft (101) and the brake puck (100).
BRAKE ASSEMBLY (Code 3) Assembly Character #7 in the model number code = 3 1. If removed, install brake pawl on brake shaft. Refer to figure 29 for orientation Example: ZX-XXXX-3XXX-XXXX NOTE: Apply a thin coating of oil to the O-rings before installing. Refer to Figure 30-31 Disassembly 1. Remove the center section per detail on page 31. NOTE: Take note of the orientation of the brake pawl (100) and the brake shaft (101). 2. Remove the brake shaft (101) and the brake pawl (100).
CENTER SECTION KIT Refer to Figure 32 Disassembly Assembly 1. Remove the bypass plate (22) from the center section. 1. Install the charge relief kit (202). Beginning with the ball, then the spring, followed by, the cross pin. 2. Remove the plug seals (26) and discard. Refer to figure 31, on page 35. IMPORTANT: Before removing the check plugs, it is important to note their specific location, i.e.
CHECK PLUGS & SEALS CYLINDER BLOCKS Refer to Figure 33 Refer to Figure 34 In order to gain access to the check plugs (24 & 25), it is necessary to remove the plug seals (26). This is accomplished by inserting a seal hook or puller into, and through, one of the insertion points (rectangular recesses) on the plug seal, refer to figure 31. After successfully removing the plug seals, discard and replace with new seals. Inspect each component of the cylinder block assemblies for wear or damage.
AXLE SHAFT (ZT-2800®/ZT-3100®) Refer to Figure 35 Disassembly Assembly 1. Remove all items beginning on page 14. 1. Assemble items in reverse order of disassembly. 2. Remove the retaining ring (90). 3. Remove and discard the lip seal (96). 4. Remove the axle shaft (94) in the direction of arrow. 5. Remove the bearing (95).
AXLE SHAFT (ZT-3200TM/ZT-3400®) Refer to Figure 36 Disassembly Inspection 1. Remove all items beginning on page 14. 1. Inspect the splines on the axle shaft for wear or damage. Replace if necessary. 2. Remove the axle tube (165). 2. Inspect the bearing (95) for wear or damage. Replace if necessary. 3. Remove the retaining ring (90). 4. Remove and discard the lip seal (96). 5. Remove the spacer (164). 6. Remove the axle shaft (94) in the direction of arrow. 6. Remove the bearing (95).
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 exploded views, and are also keyed to the complete unit exploded views on pages 42 and 44. 1. Install the axle shaft. See pages 36 or 37.. 2. Install the hydraulic components.
SIDE COVER – SCREW TIGHTENING SEQUENCE Starting with the number “1” screw location, tighten sequentially through to “16.” Torque each screw to 105 - 155 lb-in (11.87 - 17.52 Nm). NOTE: As a general rule, use the low end of the torque specification.
HOW TO USE THE SERVICE SCHEMATIC (Online) 1. Locate the transaxle model number located on the transaxle. Refer to page 6. 2. Become familiar with the model number code by associating model number code characters to component parts/unit attributes. See example below: Model No. Z H - H C E E - 3 J D B - 2 B L X Character 1 2 - 3 4 5 6 - 7 8 9 10 - 11 12 13 14 Attribute Series Axle Side & Charge Pump Rotation Axle End, Studs & Length Check Valve Rot.
NOTES ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400® 43
ZT-2800®/ZT-3100 ®/ZT-3200 TM TRANSAXLE EXPLODED VIEW 44 ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400®
ZT-2800®/ZT-3100 ®/ZT-3200 TM TRANSAXLE PARTS LIST 1 Housing, Main 102 Handle, Brake 2 Cover, Side 103 Clip, Retaining 5 Plug 9/16-18 (Metal) 105 Screw, Hex Flange Head 1/4-20 x .75 7 Screw, Hex head 1/4-20 x 1.25” 106 Guard, Filter 10 O-ring, -111,.103 x .424 109 Spacer 11 Plug, 9/16-18 (Metal) 111 Fitting, STR 9/16-18 SAE .5 BARB 13 Sealant (Loctite 5900) 120 Fan 7.
ZT-3400® TRANSAXLE EXPLODED VIEW 46 ZT-2800®/ZT-3100®/ZT-3200TM/ZT-3400®
ZT-3400® TRANSAXLE PARTS LIST 1 2 5 7 10 11 13 14 20 22 23 24 25 26 27 30 31 32 33 34 35 40 41 42 43 44 45 46 47 50 51 52 53 54 55 56 57 60 64 65 69 70 71 72 73 74 80 81 82 83 90 91 92 93 94 95 Housing, Main Cover, Side Plug 9/16-18 (Metal) Screw, Hex head 1/4-20 x 1.25” O-ring, -111,.103 x .424 Plug, 9/16-18 (Metal) Sealant (Loctite 5900) Oil, 20W50 Center Section Plate, Bypass Filter, Oil Check Plug/Shock Valve Check Plug/Shock Valve Seal, Plug 1.250 x .250 Bolt, Center Section 3/8-16 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.
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