Chapter 5: Chain Case; About This Chapter; Chain Case Operation: Drive Paths - MTD 450 Series Shop Manual

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About this chapter

This chapter covers operation and internal servicing of the chain case. Before opening the chain case, review the
troubleshooting section of this chapter to identify the most likely problem. Do not disassemble the chain case to look
for an internal problem without first eliminating all of the external possibilities.
The troubleshooting section of this chapter can also be used to help identify problems in the chain case. Use this
insight to guide you in repairing the chain case.
It is not necessary to completely disassemble the entire chain case for every repair. After the initial examination
when the chain case is separated, disassembly should be targeted to reach the identified or suspected internal prob-
lem.
This chapter is divided into three sections:
1. Chain case operation: A description of the drive paths within the chain case.
2. Chain case repair: Specific disassembly and reassembly instructions.
3. Troubleshooting chart: A guide to identifying drive problems with the tiller.

Chain Case Operation: Drive paths

Understanding the drive paths can help a technician diagnose internal problems with the chain case. The first
section of this chapter will describe the drive paths associated with each operating mode of the tiller.
1
4
2
3
6
7
Figure 5.1

CHAPTER 5: CHAIN CASE

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Chain case component groups: See Figure 5.1.
1. Shift fork: Slides on the detent shaft, moving the
input spur gear to engage the tine and wheel drive
gears.
2. Input shaft: Hexagonal shaft drives input spur gear.
The input spur gear slides on the hex shaft to engage
different gears on the Main shaft and Counter Shaft
3. Main shaft: Supports the wheel drive and the tine
drive gears.
4. Counter shaft: Carries gears to drive the tines for-
ward and the wheels in reverse.
5. Tine shaft: Driven by a sprocket on the main shaft
6. Wheel speed reduction shaft: Carries a sprocket
driven by a gear on the main shaft
7. Wheel axle: Driven by a sprocket on the wheel
speed reduction gear.
Chain Case
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