Cherokee 2WD L6-4.0L VIN S (1998)
Starter Motor: Description and Operation
SYSTEM OPERATION
The starter motor incorporates several features to create a reliable, efficient, compact, and lightweight unit. A planetary gear system (intermediate
transmission) is used between the electric motor and the pinion gear. This feature makes it possible to reduce the dimensions of the starter. At the
same time, it allows higher armature rotational speed and delivers increased torque through the pinion gear to the starter ring gear on the automatic
transmission torque converter or torque converter drive plate, or on the manual transmission flywheel.
The use of a permanent magnet field also reduces the size and weight of the starter. The permanent magnet field consists of four high-strength
permanent magnets. The magnets are aligned according to their polarity, and are permanently mounted in the starter field frame.
The starter motors for all engines are activated by a solenoid mounted to the overrunning clutch housing. However, the starter motor and solenoid
are serviced only as a complete assembly If either component is faulty or damaged, the entire starter assembly must be replaced.
CAUTION:
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Permanent magnet starters are highly sensitive to hammering, shocks, and external pressure. The permanent magnets may be damaged and the
starter rendered unserviceable, if subjected to any of these conditions.
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The starter motor must not be clamped in a vise by the starter field frame. Doing so may damage the permanent magnets. The starter should
only be clamped by the mounting flange.
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Do not connect the starter motor incorrectly when testing. Reverse polarity may damage the permanent magnets and render the starter
unserviceable.
