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Craftsman
Front-Engine Lawn Tractor

Model # 9178400 Official Craftsman heavy-duty riding unit

Here are the diagrams and repair parts for Official Craftsman 9178400 heavy-duty riding unit, as well as links to manuals and error code tables, if available.

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Model diagram and schematic

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ALL PARTS
Showing 10 of 208 parts  |
E-ring 98000071
E-ring

Part #98000071

Replaced by #812000029

?
Manufacturer substitution
This part replaces 98000071. Substitute parts can look different from the original.
BEST SELLER
This item is not returnable
$3.50
| 
22% OFF Phone Price : $4.50
In Stock
Pin 786026
#50

Transaxle diagram

Pin

Part #786026

Replaced by #786026B

?
Manufacturer substitution
This part replaces 786026. Substitute parts can look different from the original.
BEST SELLER
This item is not returnable
$4.60
| 
18% OFF Phone Price : $5.60
In Stock
Washer 19252016
Washer

Part #19252016

Replaced by #532121749

?
Manufacturer substitution
This part replaces 19252016. Substitute parts can look different from the original.
This item is not returnable
$3.98
| 
20% OFF Phone Price : $4.98
In Stock
Lock Nut 03510500
Lock nut

Part #03510500

The manufacturer no longer makes this part, and there's no substitute part

Ring 792001
#3

Transaxle diagram

Ring

Part #792001

Replaced by #792001

?
Manufacturer substitution
This part replaces 792001. Substitute parts can look different from the original.
This item is not returnable
$4.37
In Stock
Screw 17860412
#59

Seat and drive assembly diagram

Screw

Part #17860412

The manufacturer no longer makes this part, and there's no substitute part

Axle Rh 774045
#15A

Transaxle diagram

Axle rh

Part #774045

Replaced by #774068

?
Manufacturer substitution
This part replaces 774045. Substitute parts can look different from the original.
$95.40
In Stock
Gear 778039
#53

Transaxle diagram

Gear

Part #778039

Replaced by #799023

?
Manufacturer substitution
This part replaces 778039. Substitute parts can look different from the original.
$119.68
In Stock
Bearing 780055
#58

Transaxle diagram

Bearing

Part #780055

Replaced by #780055

?
Manufacturer substitution
This part replaces 780055. Substitute parts can look different from the original.
$24.51
In Stock
Shiftr Rod 784055
#14

Transaxle diagram

Shiftr rod

Part #784055

Replaced by #784055

?
Manufacturer substitution
This part replaces 784055. Substitute parts can look different from the original.
$17.86
In Stock

Most common symptoms to help you fix your riding mowers & tractors

Choose a symptom to see related riding mower and lawn tractor repairs.

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Why is my riding mower not cutting evenly?

Main causes: unlevel mower deck, dull or damaged cutting blades, worn mandrel pulleys, bent mower deck, engine needs tun...

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Why won't my riding mower start?

Main causes: dead battery, stale fuel, bad starter solenoid, ignition system problem, bad ignition interlock switch, clo...

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Why is the steering loose on my riding mower?

Main causes: damaged tie rods, bent or worn wheel spindle, worn front axle, damaged sector gear assembly...

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How do I fix a flat tire on my riding mower?

Main causes: punctured tire or inner tube, leaky valve stem, damaged wheel rim...

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Why won't my riding mower cut grass?

Main causes: worn or broken blade belt, broken belt idler pulley, blade clutch cable failure, bad PTO switch, damaged ma...

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How do I charge a dead battery on my riding mower?

Main causes: faulty battery, bad alternator...

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Why does my riding mower deck vibrate?

Main causes: damaged cutting blade, worn deck pulley, damaged mandrel pulley, loose fasteners on mower deck components...

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Why does my riding mower creep in neutral?

Main causes: shift lever needs adjustment, neutral control needs adjustment...

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Why won't my riding mower move?

Main causes: worn or broken ground drive belt, bad seat switch, transaxle freewheel control engaged, transaxle failure, ...

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Most common repair guides to help fix your riding mowers & tractors

These step-by-step repair guides will help you safely fix what’s broken on your riding mower or lawn tractor.

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How to replace the seat switch on a riding lawn mower

How to replace the seat switch on a riding lawn mower

Follow the steps in this guide to install a new riding mower seat switch in about 15 minutes....

Read more
Repair difficulty
Time required
15 minutes or less
How to replace a riding lawn mower spark plug

How to replace a riding lawn mower spark plug

If the engine is hard to start or if the spark plug electrode is burnt or cracked, take 15 minutes to replace it....

Read more
Repair difficulty
Time required
15 minutes or less
How to replace a riding lawn mower rear tire

How to replace a riding lawn mower rear tire

Your mower can’t run on a damaged rear tire. Here’s how to install a new one....

Read more
Repair difficulty
Time required
60 minutes or less

Effective articles & videos to help repair your riding mowers & tractors

Use the advice and tips in these articles and videos to get the most out of your riding mower or lawn tractor.

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How to enjoy all the online benefits we offer on our Sears PartsDirect website

How to enjoy all the online benefits we offer on our Sears PartsDirect website

Learn about all the convenient features on our Sears PartsDirect website that make your parts purchases easier....

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Top questions about Sears and Sears PartsDirect

Top questions about Sears and Sears PartsDirect

Get answers to frequently asked questions about Sears and Sears PartsDirect....

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Riding lawn mower engine clicks but doesn't turn over video

Riding lawn mower engine clicks but doesn't turn over video

Check the starter solenoid, starter motor, wiring, battery and engine....

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