- This part is in stock in our warehouse and will ship out within 1 business day of the order being placed.
- New stock is on the way! On order parts usually ship within 7 business days.
- Item is not in stock and usually ships 10-15 business days from the time you place your order.
- This item is no longer being made by the manufacturer, and cannot be added to your shopping cart.
Transmission 121-9178
- Manufactured by:
- Toro
- ERP Number:
- ERP9884543
- Part Number:
- 121-9178
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?Troubleshooting
- Toro
- Lawn Mower
Customer Part Reviews
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Customer Repair Instructions
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part.
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The lawn mower was no longer self propelled
Michael from Madison, Connecticut
- Difficulty Level:
- A Bit Difficult
- Total Repair Time:
- 1- 2 hours
- Tools:
- Pliers, Socket set, Wrench set
a. Removed the handle, plastic and metal shrouds underneath,
b. Removed the drive wheels and metal side plates holding the transmission.
c. Loosened the belt guide at the engine.
d. Removed the drive belt.
e. Removed the transmission from ... Read more the side plates. Detach from the control cable.
2. Install the new drive belt around the engine pulley, Tighten the belt guide.
3. Do the reverse of the dis-assembly. Grease all rotating parts
4. Start lawn mower and check operation.
Transmission stopped pulling on my Toro personal pace walk behind mower
Alan from Brandon , Mississippi
- Difficulty Level:
- A Bit Difficult
- Total Repair Time:
- 1- 2 hours
- Tools:
- Screw drivers, Socket set, Wrench set
Lawn Mower would not self propel
Paul from Arlington Heights, Illinois
- Difficulty Level:
- A Bit Difficult
- Total Repair Time:
- 1- 2 hours
- Tools:
- Nutdriver, Screw drivers, Socket set, Wrench (Adjustable), Wrench set
- Parts Used:
- 121-9178
Lost self propelled
Glenn from ERIE, Colorado
- Difficulty Level:
- A Bit Difficult
- Total Repair Time:
- 30 - 60 mins
- Tools:
- Nutdriver, Socket set
- Parts Used:
- 121-9178
Removed blade
Removed belt covers
Removed belt
Removed axle pins
Slid out axle/transmission assembly and replaced it
Mower needed a new transmission
David from SNELLVILLE, Georgia
- Difficulty Level:
- A Bit Difficult
- Total Repair Time:
- 30 - 60 mins
- Tools:
- Nutdriver, Pliers, Socket set, Wrench (Adjustable), Wrench set
- Parts Used:
- 121-9178
Transmission lock-up, worn belt, failed wheel bearings, cracked wheel covers
Kris from PINE, Arizona
- Difficulty Level:
- Easy
- Total Repair Time:
- 30 - 60 mins
- Tools:
- Pliers, Screw drivers, Socket set, Wrench set
Popping in transmission
Roger from Alpharetta, Georgia
- Difficulty Level:
- A Bit Difficult
- Total Repair Time:
- 1- 2 hours
- Tools:
- Pliers, Screw drivers, Socket set, Wrench (Adjustable), Wrench set
Transmission failed
L from Covington, Louisiana
- Difficulty Level:
- Easy
- Total Repair Time:
- 30 - 60 mins
- Tools:
- Pliers, Screw drivers, Socket set, Wrench set
- Parts Used:
- 121-9178
2. After disassembly found that the bushing and bearings on for the axle were bad.
3. When replacing transmission also get the bushing and bearings for the axle
4. Pick up at local shop and replaced both sides
5. The actual wor ... Read more k time was about on hour.
Rear-wheel drive wheel would spin when making a turn (transmission). Rear wheel squeak (bearing).
Ralph from EMMAUS, Pennsylvania
- Difficulty Level:
- A Bit Difficult
- Total Repair Time:
- 1- 2 hours
- Tools:
- Screw drivers, Socket set
2. Remove drive belt covers.
3. Remove one rear wheel support bracket.
4. Remove transmission.
5. Remove bearing from each rear wheel support bracket.
6. Re-assemble in reverse directions.
Transmission pulley wore out
JAMES from Laredo, Texas
- Difficulty Level:
- Easy
- Total Repair Time:
- 1- 2 hours
- Tools:
- Socket set
- Parts Used:
- 121-9178
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Model Cross Reference
Manufacturer Part Number: 121-9178
| Brand | Model Number | Description |
|---|---|---|
| Toro | 20332 | Lawn Mower - Lawn Mower |
| Toro | 20332C | Lawn Mower - Lawn Mower |
| Toro | 20333 | Lawn Mower - Lawn Mower |
| Toro | 20333C | Lawn Mower - Lawn Mower |
| Toro | 20334 | Lawn Mower - Lawn Mower |
| Toro | 20334C | Lawn Mower - Lawn Mower |
| Toro | 20337 | Lawn Mower - Toro Lawn Mower Model 20337/Serial: 314000001-314999999/2014 (20337/Serial:314000001314999999/2014, 20337/Serial: 314000001 314999999/2014) Parts |
| Toro | 20337HD | Lawn Mower - 22in Recycler Lawn Mower |
| Toro | 20352 | Lawn Mower - Lawn Mower |
| Toro | 20353 | Lawn Mower - Toro Lawn Mower Model 20353/Serial: 315000001-315999999/2015 (20353/Serial:315000001315999999/2015, 20353/Serial: 315000001 315999999/2015) Parts |
| Toro | 20372 | Lawn Mower - 22in Recycler Lawn Mower |
| Toro | 20373 | Lawn Mower - 22in Recycler Lawn Mower |
| Toro | 20374 | Lawn Mower - 22in Recycler Lawn Mower |
| Toro | 20376 | Lawn Mower - Toro Lawn Mower Model 20376 Parts |
| Toro | 20955 | Lawn Mower - Toro Lawn Mower Model 20955/SERIAL: 313000001-313999999 (20955/SERIAL:313000001313999999, 20955/SERIAL: 313000001 313999999) Parts |
| Toro | 20956 | Lawn Mower - Toro Lawn Mower Model 20956/SERIAL: 313000001-313999999 (20956/SERIAL:313000001313999999, 20956/SERIAL: 313000001 313999999) Parts |
| Toro | 20958 | Lawn Mower - Toro Lawn Mower Model 20958/SERIAL: 313000001-313999999 (20958/SERIAL:313000001313999999, 20958/SERIAL: 313000001 313999999) Parts |
| Toro | 20960 | Lawn Mower - Toro Lawn Mower Model 20960/Serial: 315000001-315999999/2015 (20960/Serial:315000001315999999/2015, 20960/Serial: 315000001 315999999/2015) Parts |
| Toro | 20964 | Lawn Mower - 55cm Recycler Lawn Mower |
| Toro | 21762 | Lawn Mower - 55cm Recycler Lawn Mower |
| Toro | 21763 | Lawn Mower - 55cm Recycler Lawn Mower |
| Toro | 21764 | Lawn Mower - 21764, 55cm Recycler Lawn Mower, (Sn 400000000-999999999) |
| Toro | 21766 | Lawn Mower - 55cm Recycler Lawn Mower |
| Toro | 21767 | Lawn Mower - 55cm Recycler Lawn Mower |
Some of the parts we sell are eligible for mail-in rebates since we can recycle them. We will display any applicable rebates in your shopping cart. To redeem your rebate, contact Customer Service after you have received your part.