1990-2002 Lawn-Boy 10521 Walk-Behind Mower Service/Shop Repair Manual
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TORO/LAWN-BOY WALK BEHIND POWER MOWER DRIVE SYSTEMS MANUAL
Table of Contents – Page 1 of 2
TRANSMISSION USAGE
WORM DRIVE TRANSMISSION
SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION
SINGLE SPEED BEVEL GEAR TRANSMISSION
THREE SPEED TRANSMISSION
WORM DRIVE TRANSMISSION
GENERAL
INTERNALLY CLUTCHED
DESCRIPTION
LUBRICATION
THE SHIFTING PROCESS
REMOVAL AND INSTALLATION (FRONT WHEEL DRIVE APPLICATIONS)
DISASSEMBLY
ASSEMBLY
CONTROLS
ADJUSTMENT
CONSTANT MESH
DESCRIPTION
REMOVAL AND INSTALLATION
CONTROLS
SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION
GEAR CASE ASSEMBLY
INTRODUCTION
LUBRICATION
DISASSEMBLY
ASSEMBLY
CABLE ADJUSTMENT
SINGLE SPEED BEVEL GEAR TRANSMISSION
EXPLODED VIEW - SINGLE SPEED BEVEL GEAR TRANSMISSION
GENERAL INFORMATION
FRONT AXLE AND TRANSMISSION ASSEMBLY
FRONT WHEEL DRIVE MODELS
TRANSMISSION DISASSEMBLY
TRANSMISSION DISASSEMBLY
TRANSMISSION ASSEMBLY
ASSEMBLY TIPS
BELT SERVICE - FRONT WHEEL DRIVE MODELS
REAR WHEEL DRIVE MODELS
TRANSMISSION REMOVAL AND BELT REPLACEMENT
REAR AXLE DISASSEMBLY
TRANSMISSION DISASSEMBLY
TRANSMISSION ASSEMBLY
AXLE ASSEMBLY TIPS
WHEEL PINION SERVICE
22" STEEL DECK TRACTION ADJUSTMENTS
BAIL CONTROL
PERSONAL PACE
TORO/LAWN-BOY WALK BEHIND POWER MOWER DRIVE SYSTEMS MANUAL
Table of Contents – Page 2 of 2
THREE SPEED TRANSMISSION
GEARCASE ASSEMBLY
OPERATION
REMOVAL - TORO VACU POWER/LAWN-BOY MEDALLION MODELS
REMOVAL - RECYCLER/REAR BAGGER CHASSIS
ALTERNATE METHOD
DISASSEMBLY
TRANSMISSION - ASSEMBLY
OUTPUT SHAFT ASSEMBLY
INPUT SHAFT ASSEMBLY
INTERMEDIATE SHAFT ASSEMBLY
INSTALLATION
SPECIAL ASSEMBLY NOTES FOR TORO VACU POWER/LAWN-BOY MEDALLION
TROUBLESHOOTING TIPS - 3 SPEED TRANSMISSION
HARD SHIFTING
SLIPPING GEARS
CABLE ADJUSTMENT
WHEEL PINION CLUTCH
GEARCASE AND WHEEL ASSEMBLY
REAR HEIGHT-OF-CUT AND WHEEL PINION CLUTCH - DISASSEMBLY
REAR HEIGHT-OF-CUT AND WHEEL PINION CLUTCH - ASSEMBLY
BLADE BRAKE CLUTCH SYSTEMS (BBC)
CLUTCH OPERATION
CONTROL BOX OPERATION
HANDLE CONTROLS
CONTROL BOX DISASSEMBLY
CONTROL BOX ASSEMBLY
TORO BBC SERVICE GUIDE
BLADE BRAKE CLUTCH ASSEMBLY (TORO VACU POWER / LAWN-BOY MEDALLIION)
TORO VACU POWER LAWN-BOY / MEDALLION BBC
BELLCRANK SYSTEM DISASSEMBLY (TORO VACU POWER / LAWN-BOY MEDALLION)
BELLCRANK SYSTEM ASSEMBLY (TORO VACU POWER / LAWN-BOY MEDALLION)
UNDER DECK COMPONENTS DISASSEMBLY
(TORO VACU POWER / LAWN-BOY MEDALLION)
UNDER DECK COMPONENTS ASSEMBLY
(TORO VACU POWER / LAWN-BOY MEDALLION)
BBC CABLE REMOVAL (TORO VACU POWER / LAWN-BOY MEDALLION)
BBC CABLE INSTALLATION (TORO VACU POWER / LAWN-BOY MEDALLION)
BBC CABLE ADJUSTMENT (TORO VACU POWER / LAWN-BOY MEDALLION MODELS)
ENGINE AND BLADE ASSEMBLY (TORO RECYCLER / REAR BAGGER)
TORO RECYCLER / REAR BAGGER BBC
IDLER ARM SYSTEM DISASSEMBLY (RECYCLER / REAR BAGGER)
IDLER ARM SYSTEM ASSEMBLY (RECYCLER / REAR BAGGER)
BBC CABLE REMOVAL (RECYCLER / REAR BAGGER)
BBC CABLE INSTALLATION (RECYCLER / REAR BAGGER)
BBC CABLE ADJUSTMENT (RECYCLER / REAR BAGGER)
WALK BEHIND POWER MOWER
DRIVE SYSTEMS
SERVICE MANUAL
ABOUT THIS MANUAL
This service manual was written expressly for Toro servicing dealers. The Toro Company
has made every effort to make the information in this manual complete and correct.
This manual was written with the assumption that the reader has basic mechanical
knowledge and skills. This book contains material covering the Toro and Lawn-Boy Walk
Behind Mower Drive Systems models from 1990 to 2002, and may be specified for use on
products built after 2002 that are similar in design.
We hope you find this manual a valuable addition to your service shop. If you have
questions or comments regarding this manual, please contact us at the following address:
The Toro Company
Consumer Service Department
8111 Lyndale Avenue South
Bloomington, MN 55420-1196
The Toro Company reserves the right to change product specifications or this manual
without notice.
Copyright© All Rights Reserved
©2001 The Toro Company
Walk Behind Power Mower Drive Systems Manual i
TABLE OF CONTENTS
TRANSMISSION USAGE
Worm Drive Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Single Speed Spur/Bevel Gear Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Single Speed Bevel Gear Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Three Speed Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
WORM DRIVE TRANSMISSION
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 1
Internally Clutched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 1
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 2
The Shifting Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 2
Removal and Installation (front wheel drive applications) . . . . . . . . . . . . . . . . . .1 - 3
Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 4
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 6
Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 8
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 8
Constant Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 9
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 9
Removal And Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 10
Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 - 11
SINGLE SPEED SPUR/BEVEL GEAR TRANSMISSION
Gear Case Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 - 2
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 - 2
Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 - 2
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 - 4
Cable Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 - 4
TABLE OF CONTENTS
ii Walk Behind Power Mower Drive Systems Manual
SINGLE SPEED BEVEL GEAR TRANSMISSION
Exploded View - Single Speed Bevel Gear Transmission . . . . . . . . . . . . . . . . . . . 3 - 1
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 2
Front Axle And Transmission Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3
Front Wheel Drive Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4
Transmission Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4
Transmission Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 5
Transmission Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 6
Assembly Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 6
Belt Service - Front Wheel Drive Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 7
Rear Wheel Drive Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 8
Transmission Removal and Belt Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 8
Rear Axle Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 11
Transmission Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 13
Transmission Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 13
Axle Assembly Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 13
Wheel Pinion Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 14
22” Steel Deck Traction Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 15
Bail Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 15
Personal Pace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 16
Walk Behind Power Mower Drive Systems Manual iii
TABLE OF CONTENTS
THREE SPEED TRANSMISSION
Gearcase Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 1
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2
Removal - Toro Vacu Power/Lawn-Boy Medallion Models . . . . . . . . . . . . . . . . .4 - 3
Removal - Recycler/Rear Bagger Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 4
Alternate Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 4
Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 4
Transmission - Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 5
Output Shaft Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 5
Input Shaft Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 6
Intermediate Shaft Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 7
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 8
Special Assembly Notes For Toro Vacu Power/Lawn-Boy Medallion . . . . . . . . .4 - 8
Troubleshooting Tips - 3 Speed Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 9
Hard Shifting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 9
Slipping Gears . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 9
Cable Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 10
WHEEL PINION CLUTCH
Gearcase And Wheel Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 1
Rear Height-Of-Cut And Wheel Pinion Clutch - Disassembly . . . . . . . . . . . . . . .5 - 3
Rear Height-Of-Cut and Wheel Pinion Clutch - Assembly . . . . . . . . . . . . . . . . . .5 - 4
TABLE OF CONTENTS
iv Walk Behind Power Mower Drive Systems Manual
BLADE BRAKE CLUTCH SYSTEMS (BBC)
Clutch Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 1
Control Box Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 1
Handle Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 2
Control Box Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 4
Control Box Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 5
Toro BBC Service Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 7
Blade Brake Clutch Assembly (Toro Vacu Power / Lawn-Boy Medalliion) . . . . . . . 6 - 8
Toro Vacu Power Lawn-Boy / Medallion BBC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 9
Bellcrank System Disassembly (Toro Vacu Power / Lawn-Boy Medallion) . . . . 6 - 9
Bellcrank System Assembly (Toro Vacu Power / Lawn-Boy Medallion) . . . . . . 6 - 10
Under Deck Components Disassembly
(Toro Vacu Power / Lawn-Boy Medallion) . . . . . . . . . . . . . . . . . . . . . . . 6 - 11
Under Deck Components Assembly
(Toro Vacu Power / Lawn-Boy Medallion) . . . . . . . . . . . . . . . . . . . . . . . 6 - 14
BBC Cable Removal (Toro Vacu Power / Lawn-Boy Medallion) . . . . . . . . . . . 6 - 16
BBC Cable Installation (Toro Vacu Power / Lawn-Boy Medallion) . . . . . . . . . . 6 - 16
BBC Cable Adjustment (Toro Vacu Power / Lawn-Boy Medallion Models) . . . 6 - 17
Engine And Blade Assembly (Toro Recycler / Rear Bagger) . . . . . . . . . . . . . . . . . 6 - 19
Toro Recycler / Rear Bagger BBC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 20
Idler Arm System Disassembly (Recycler / Rear Bagger) . . . . . . . . . . . . . . . . 6 - 20
Idler Arm System Assembly (Recycler / Rear Bagger) . . . . . . . . . . . . . . . . . . . 6 - 22
BBC Cable Removal (Recycler / Rear Bagger) . . . . . . . . . . . . . . . . . . . . . . . . 6 - 24
BBC Cable Installation (Recycler / Rear Bagger) . . . . . . . . . . . . . . . . . . . . . . . 6 - 25
BBC Cable Adjustment (Recycler / Rear Bagger) . . . . . . . . . . . . . . . . . . . . . . 6 - 26
Walk Behind Power Mower Drive Systems Manual v
TABLE OF CONTENTS
TRANSMISSION USAGE
Worm Drive Transmission
Single Speed Spur/Bevel Gear Transmission
Single Speed Bevel Gear Transmission
Three Speed Transmission
Toro Models
16212
16212B
16212W
16212WG
16401
16402
16403
16404
16411
16775
16776
16785
16793
20905
20905B
20906B
20911B
20915
20916B
20920
20920B
20921B
20925
20925B
20926B
20927B
Toro Models Lawn-Boy Models
20011
20020
20021
20028
20442
20444
20711
10301
10302
10304
10305
10307
10309
10310
10311
10312
10313
10314
10316
10317
10318
10319
10320
10321
10323
10324
10324C
10327
10328
10329
10330
10331
10332
10334
10335
10342
10343
10344
10345
10360
10360C
10361
10362
10363
10550
10551
10552
10910
10910B
10915
10915B
10926
10927
10929
Toro Models
20012
20013
20014
20016
20017
20018
Toro Models Lawn-Boy Models
20044
20106
20210
20211
20214
20216
20218
20219
20320
20321
20322
20324
20325
20327B
20328B
20436
20436WF
20437
20438
20438WF
20439
20439WF
20462
20463
20464
20465
20466
20470
20472
20473
20474
20475
20476
20478
20479
20480
20481
20482
20483
20486
20487
20488
20489
20490
20494
20495
20622
20666
20667
20668
20677
20680
20692
20761B
20763B
20764B
20764BC
20766B
20766BC
20767B
20768B
20776
20777
20778
20786
20787
22035
22036
22037B
22037BC
22038
22038B
22040
22042
22043
22044BC
22045
22045B
22141
22142
22150
22151
22153BC
22154
22154B
22157
26620B
26620BF
26620BG
26621
26621B
26622
26623
26624
26625B
26625BG
26626
26630B
26630BC
26630BG
26631B
26631BC
26632
26632B
26633
26633B
26635B
226635BC
26635BG
26636
26636B
26637
26638
26639
26640B
26640BC
26643
26643B
26680
26680WG
26682
26683
27500
27501
27502
10515
10516
10517
10518
10519
10520
10521
10522
10523
10524
10525
10527
10528
10533
10545
10546
10547
10548
10590
10591
10750
10760
10761B
10762B
10928
11001
11001B
11003
vi Walk Behind Power Mower Drive Systems Manual
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This service/shop repair manual is a comprehensive guide for vehicle owners, covering everything from basic maintenance to complex repairs. With a substantial page count and numerous illustrations, it provides detailed instructions for identifying and resolving issues, such as oil changes and transmission replacements. The manual features user-friendly text and a search function for easy navigation, along with the option to print specific pages. Whether you're a professional mechanic or a DIY enthusiast, this Factory Service Repair Manual offers step-by-step guidance on maintenance and repairs, empowering you to make informed decisions about your vehicle. Rest assured, along with the high-quality manual, we are committed to providing excellent customer service to ensure your satisfaction.
