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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
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
Roll Pin 792002
#4

Transaxle diagram

Roll pin

Part #792002

Replaced by #792049

?
Manufacturer substitution
This part replaces 792002. Substitute parts can look different from the original.
This item is not returnable
$6.77
In Stock
Gear 778036
#43

Transaxle diagram

Gear

Part #778036

Replaced by #778036

?
Manufacturer substitution
This part replaces 778036. Substitute parts can look different from the original.
$70.64
In Stock
Diff Carrier 774029
#69

Transaxle diagram

Diff carrier

Part #774029

Replaced by #774029A

?
Manufacturer substitution
This part replaces 774029. Substitute parts can look different from the original.
$79.96
In Stock
Spur 778024
#40

Transaxle diagram

Spur

Part #778024

Replaced by #778024A

?
Manufacturer substitution
This part replaces 778024. Substitute parts can look different from the original.
$26.29
In Stock
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
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

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

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

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 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.…

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Repair difficulty
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 15 minutes or less
How to replace a riding lawn mower rear tire

How to replace a riding lawn mower rear tire

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Repair difficulty
Time required
 60 minutes or less

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

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Top questions about Sears and Sears PartsDirect

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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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Riding mower and tractor common questions

Riding mower and tractor common questions

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