Page 2 - Table of Contents; Description
BDU-10/21 BDU-10/21 Table of Contents Description Page Introduction ...................................................................................................... 3General Description ....................................................................................... 3-5Fluids. ............
Page 3 - Introduction/General Description
BDU-10/21 BDU-10/21 The fluid supply for the BDU-10L/21L transmission iscontained in an external reservoir and passes through anexternal filter prior to entering the transmission and feedingthe fixed displacement gerotor charge pump. Excess fluid in the charge circuit is discharged over the charge r...
Page 4 - General Description; BDU-10S Hydrostatic Flow Illustration
BDU-10/21 BDU-10/21 Page 4 General Description The BDU-21L transmission offers an optional Implement(auxiliary) pump. The auxiliary circuit provides a rated flowof 1.5 gpm (5.67 l/min) and 500 PSI (34.5 bar) operatingpressure at a 3200 RPM pump speed. Fluid from the charge pump flows first to the im...
Page 5 - General Description; BDU-10L/21L Hydrostatic Flow Illustration
BDU-10/21 BDU-10/21 Page 5 General Description BDU-21L/A Hydrostatic Flow Illustration BDU-10L/21L Hydrostatic Flow Illustration
Page 6 - SAE VISCOCITY GRADES; Safety Precautions
BDU-10/21 BDU-10/21 Page 6 Maintenance BDU-21L/A BDU-10L Maintenance Check the transmission cooling fan for broken or distortedblades, and check to see that the fan is securely fastened.Replace the fan if damaged. Keep the transmission clean. Grass clippings and dirt willinfluence the cooling effici...
Page 7 - Troubleshooting Diagram; OPERATING HOT/LOSING POWER
BDU-10/21 BDU-10/21 Page 7 Troubleshooting Diagram OPERATING HOT/LOSING POWER OPERATES IN ONE DIRECTION ONLY NOISY UNDER LOAD
Page 8 - Troubleshooting Chart
BDU-10/21 BDU-10/21 WARNING!!! THE VEHICLE SHOULD BE ON LEVEL GROUND AND THE ENGINE DISABLED BEFORE PERFORMING ANY ADJUSTMENTS Page 8 Troubleshooting Chart SYMPTOM - OPERATES IN ONE DIRECTION ONLY POSSIBLE CAUSE CORRECTIVE ACTION -Inspect control linkage -Repair or replace -Inspect drive belt & ...
Page 9 - Minor Repair; Retaining Ring Removal
BDU-10/21 BDU-10/21 General Information Minor repairs may be performed, following the proceduresin this section, without voiding the unit warranty. Cleanliness is a primary means of assuring satisfactory lifeon either new or repaired units. Cleaning parts by usingsolvent wash and air drying is usual...
Page 10 - Shaft Seals; Lip Seal Installation; Charge Check Valves; Check Valve Removal/ Installation
BDU-10/21 BDU-10/21 Shaft Seals Inspect the sealing area on the shaft for rust, wear, orcontamination. Polish the sealing area on the shaft ifnecessary. Wrap the spline or keyed end of the shaft with with a thinplastic or cellophane to prevent damage to the seal lipduring installation. Lubricate the...
Page 11 - Bypass Valve
BDU-10/21 BDU-10/21 Minor Repair Page 11 Bypass Valve Easy Ride Valve Inspect the check balls (or poppets) and mating seats inthe center section for damage or foreign material. Position the transmission so that the check valve port willbe in the upright position (as shown) and install the checkball ...
Page 12 - Charge Pump; BDU-10L With Through Shaft Charge Pump
BDU-10/21 BDU-10/21 Charge Pump The correct charge pump orientation is determined by therotation of the pump shaft (CW or CCW). Before removingthe charge pump, make note of, and/or mark its position tosimplify the reassembly process. Page 12 Minor Repair BDU-21L Aux. CCW BDU-21L CCW BDU-21L CW BDU-1...
Page 13 - BDU-10L Charge Pump Components; Disassembly Procedures
BDU-10/21 BDU-10/21 For BDU-21L: Install the charge relief valve spring and ball. Install the drive pin. Install the gerotor assembly. Install anew o-ring and the charge pump cover. NOTE: The charge relief spring must enter the recessed hole in the chargepump cover. Torque the bolts evenly to 12-15 ...
Page 14 - Major Repair; BDU-21L Charge Pump Components; General Information
BDU-10/21 BDU-10/21 Page 14 Major Repair Charge PumpAssembly Procedures For BDU-21L with implement circuit: Install the drive pin. Install a new o-ring on each side of the gerotorassembly and position the gerotor assembly onto thealigning pins in the same orientation as it was removed.Install the ch...
Page 15 - BDU-10S Center Section Removal; BDU-10S Filter Removal; Remove Cylinder Blocks
BDU-10/21 BDU-10/21 Major Repair Page 15 BDU-10S Center Section Removal BDU-10S Aligning Pins and Gasket For BDU-10S remove the filter element, filter washer and spring from the housing. Remove the pump cylinder block kit from the pump shaft.Inspect the splines on the shaft and in the pump block for...
Page 16 - 0CC and 21CC Cylinder Block Kit Components
BDU-10/21 BDU-10/21 Major Repair Page 16 Disassembly Procedures Remove the motor thrust bearing assembly from thehousing. Remove the swashplate assembly and cradle bearings(BDU-10 only) from the housing. NOTE: The cradle bearings in newer BDU-21L transmis- sions are not removable from the housing. I...
Page 17 - Housing, Control Arm and Lip Seal
BDU-10/21 BDU-10/21 Inspect the control shaft journal bearing for excessivewear. The BDU 10 control shaft journal bearing should be0.4722 to 0.4733 while the BDU 21 control shaft journalbearing should be 0.5904 to 0.5908. Inspect the BDU-10 motor shaft journal bearing for exces-sive wear. The BDU 10...
Page 18 - BDU-10 Swashplate Components; Assembly Procedures
BDU-10/21 BDU-10/21 Install the swashplate into the housing. The slot on theswashplate must engage the slot guide block on thedisplacement control shaft. Use a tool such as a screw-driver or scribe to hold the guide block in position whileinstalling the swashplate. NOTE: As a product improvement, si...
Page 19 - BDU-21 Swashplate Components; BDU-21 Swashplate Changes
BDU-10/21 BDU-10/21 Major Repair Page 19 BDU-21 Swashplate Components Measure Control Arm End Play BDU-10 Cylinder Block Kit BDU-21 with Swashplate Installed Install the thrust washer and pump cylinder block springonto the pump shaft. Install the springs piston washers and pistons into thecylinder b...
Page 20 - BDU-10 with Pump Block Installed; Assembly Procedure; BDU-10 Motor Shaft Kit Installation
BDU-10/21 BDU-10/21 Install the motor thrust bearing into the housing. NOTE: It will be necessary to have a DRY journal bearing to prevent a hydraulic lock while installing the motor shaft. Install the motor shaft/cylinder block kit. Use caution toprevent damage to the journal bearing while guiding ...
Page 21 - BDU-10 Center Section Assembly
BDU-10/21 BDU-10/21 Page 21 Major Repair BDU-10 For BDU-10 Check to see that the piston springs are centered in the cylinder block bores. If necessary, positionthem with a small screwdriver. Use caution to avoiddamage to the cylinder block face. For BDU-10S Install the filter spring, washer and new ...
Page 23 - PARTS LIST
BDU-10/21 BDU-10/21 BDU-10S Parts Drawing & Parts List Page 23 PARTS LIST . O N N O I T P I R C S E D . O N N O I T P I R C S E D 1 T F A H S P M U P 5 2 E T A L P H S A W S E L B A I R A V 2 G N I R G N I N I A T E R E R I W 0 3 L A E S P I L 3 G N I R A E B L L A B T F A H S 2 3 Y L B M E S S ...
