CLUTCH

CONTENTS

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CLUTCH DIAGNOSIS . . . . . . . . . . . . . . . . . . . . . . 1CLUTCH SERVICE . . . . . . . . . . . . . . . . . . . . . . . 10

GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1

GENERAL INFORMATION

INDEX

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Clutch Components . . . . . . . . . . . . . . . . . . . . . . . . 1Clutch Component Lubrication . . . . . . . . . . . . . . . . . 2Clutch Linkage Fluid . . . . . . . . . . . . . . . . . . . . . . . . 1

Clutch Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Clutch Pedal Position Switch . . . . . . . . . . . . . . . . . . 1Hydraulic Linkage Components . . . . . . . . . . . . . . . . 1

CLUTCH COMPONENTSThe clutch mechanism in Grand Cherokee models

consists of a single dry disc, and a diaphragm styleclutch cover. A hydraulic linkage is used to operatethe clutch release lever and bearing.

The transmission input shaft is supported in thecrankshaft flange by a pilot bearing. A sleeve type re-lease bearing is used to engage and disengage theclutch cover pressure plate. The bearing rides on thetransmission front bearing retainer.

The release bearing is operated by a fork in theclutch housing. The fork pivots on a ball stud and isoperated by the hydraulic slave cylinder piston. Theslave cylinder is mounted in the clutch housing andis operated by the clutch master cylinder. The clutchmaster cylinder is mounted on the dash panel andthe cylinder piston is connected to the clutch pedal.

The clutch disc has cushion springs in the disc huband the disc facing is riveted to the hub. The facingis made from a non-asbestos material.

The clutch cover pressure plate is a diaphragmtype with a one-piece spring and multiple release fin-gers. The pressure plate release fingers are presetduring manufacture and are not adjustable.

HYDRAULIC LINKAGE COMPONENTSThe hydraulic linkage consists of a remote reser-

voir, master cylinder, slave cylinder and interconnect-ing fluid lines.

The clutch master cylinder piston is connected tothe clutch pedal. The slave cylinder piston is con-nected to the clutch release lever. The master cylin-

der is mounted on the driver side of the dash panelnext to the brake master cylinder.

The linkage components are not serviced sepa-rately. The linkage is only serviced as a complete as-sembly.

CLUTCH LINKAGE FLUIDThe clutch fluid reservoir, master cylinder, slave

cylinder and fluid lines are pre-filled with fluid atthe factory during assembly operations.

The hydraulic system should not require additionalfluid under normal circumstances. In fact, the reser-voir fluid level will actually increase as normalclutch wear occurs. For this reason, it is impor-tant to avoid overfilling, or removing fluid fromthe reservoir.

If inspection indicates additional fluid is needed,use Mopar brake fluid, or an equivalent meetingstandards SAE J1703 and DOT 3. Do not use anyother type of fluid and only use fluid from a sealedcontainer.

CLUTCH PEDAL POSITION SWITCHA clutch pedal position switch has been added to

the starter circuit. The switch is in circuit with thestarter solenoid and requires that the clutch pedal befully depressed in order to start the engine. Switchcircuitry and operation is described in section 8W ofGroup 8.

The switch is located on the clutch master cylinderpush rod and is not serviced separately. It is servicedas part of the clutch master cylinder assembly.

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CLUTCH COMPONENT LUBRICATIONProper clutch component lubrication is important

to satisfactory operation. Using the correct lubricantand not overlubricating are equally important. Applyrecommended lubricant sparingly to avoid disc andpressure plate contamination.

Clutch and transmission components requiring lu-brication are:• pilot bearing• release lever pivot ball stud• release lever contact surfaces• release bearing bore• clutch disc hub splines• clutch pedal pivot shaft bore• clutch pedal bushings• transmission input shaft splines• transmission input shaft pilot hub• transmission front bearing retainer slide surface

Never apply grease to any part of the clutchcover, or disc.

RECOMMENDED LUBRICANTSUse Mopar multi-purpose grease for the clutch

pedal bushings and pivot shaft. Use Mopar high tem-perature grease (or equivalent) for all other lubrica-tion requirements. Apply recommended amounts anddo not overlubricate.

CLUTCH OPERATIONLeverage, clamping force, and friction are the

clutch operating principles. The disc serves as thefriction element and the cover diaphragm spring act-ing on the pressure plate provide the clamping force.The pedal, hydraulic linkage, release lever and bear-ing provide the leverage.

The clutch cover assembly consists of the cover,pressure plate, diaphragm spring and fulcrum com-

ponents. The pressure plate clamps the clutch discagainst the flywheel. Clamping force on the pressureplate, comes from the diaphragm spring.

The clutch disc has a splined hub for installationon the transmission input shaft splines. The splinedhub provides the connection to the transmission.

The clutch linkage uses hydraulic pressure to oper-ate the clutch mechanism. The clutch master cylin-der is connected to the clutch pedal and the slavecylinder is connected to the release lever.

Pressing the clutch pedal develops fluid pressure inthe clutch master cylinder. This pressure is transmit-ted to the slave cylinder through the connecting line.The slave cylinder piston then operates the clutch re-lease lever.

The clutch release bearing is mounted on thetransmission front bearing retainer. The bearing isattached to the release lever which moves the bear-ing in and out of contact with the diaphragm springfingers. The release lever is operated by the slavecylinder piston rod.

In operation, slave cylinder force exerted throughthe cylinder piston, causes the release lever to pivottoward the clutch. This action moves the releasebearing into contact with the diaphragm spring fin-gers. The release bearing pushes the spring fingersinward against the fulcrums to unload spring forceon the pressure plate. At this point, clamping forceon the disc is released allowing the disc to disengageand freewheel.

The process of clutch re-engagement, is simply thereverse of what occurs during disengagement. Releas-ing pedal pressure removes linkage pressure. The re-lease bearing moves away from the diaphragm springwhich again applies clamping force on the discthrough the pressure plate.

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CLUTCH DIAGNOSIS

INDEX

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Clutch Contamination . . . . . . . . . . . . . . . . . . . . . . . 3Clutch Cover and Disc Runout . . . . . . . . . . . . . . . . 3Clutch Housing Misalignment . . . . . . . . . . . . . . . . . 4Clutch Misalignment . . . . . . . . . . . . . . . . . . . . . . . . 3

Flywheel Runout . . . . . . . . . . . . . . . . . . . . . . . . . . . 3General Diagnosis Information . . . . . . . . . . . . . . . . 3Inspection and Diagnosis Charts . . . . . . . . . . . . . . . 4Installation Methods and Parts Usage . . . . . . . . . . . 4

GENERAL DIAGNOSIS INFORMATIONUnless the cause of a clutch problem is obvious, ac-

curate problem diagnosis will usually require a roadtest to confirm a problem. Component inspection willthen be required to determine the actual problemcause.

During a road test, drive the vehicle at normalspeeds. Shift the transmission through all gearranges and observe clutch action. If chatter, grab,slip, or improper release is experienced, remove andinspect the clutch components. However, if the prob-lem is noise or hard shifting, further diagnosis maybe needed as the transmission or another drivelinecomponent may be at fault. Careful observation dur-ing the test will help narrow the problem area.

CLUTCH CONTAMINATIONFluid contamination is a frequent cause of clutch

malfunction. Oil, water, or clutch fluid on the clutchcontact surfaces will cause chatter, slip, or grab.

During inspection, note if any components are con-taminated with oil, hydraulic fluid, or water/roadsplash.

Oil contamination indicates a leak at either therear main seal or transmission input shaft. Oil leak-age produces a residue of oil on the housing interiorand on the clutch cover and flywheel. Heat buildupcaused by slippage between the cover, disc and fly-wheel, can sometimes bake the oil residue onto thecomponents. The glaze-like residue ranges in colorfrom amber to black.

Road splash contamination means dirt/water is en-tering the clutch housing due to loose bolts, housingcracks, or through hydraulic line openings. Drivingthrough deep water puddles can force water/roadsplash into the housing through such openings.

Clutch fluid leaks are from loose or damaged slavecylinder fluid lines and connecting fittings. However,clutch fluid leaks will usually be noted and correctedbefore severe contamination occurs.

CLUTCH MISALIGNMENTClutch components must be in proper alignment

with the crankshaft and transmission input shaft.

Misalignment caused by excessive runout or warpageof any clutch component will cause grab, chatter andimproper clutch release.

FLYWHEEL RUNOUTCheck flywheel runout whenever misalignment is

suspected. Flywheel runout should not exceed 0.08mm (0.003 in.). Measure runout at the outer edge ofthe flywheel face with a dial indicator. Mount the in-dicator on a stud installed in place of one of the fly-wheel bolts.

Common causes of runout are:• heat warpage• improper machining• incorrect bolt tightening• improper seating on crankshaft flange shoulder• foreign material on crankshaft flange

Flywheel machining is not recommended. The fly-wheel clutch surface is machined to a unique contourand further machining will negate this feature.

Minor flywheel scoring can be smoothed by handwith 180 grit emery, or with surface grinding equip-ment. Remove only enough material to reduce scor-ing (approximately 0.001 - 0.003 in.). Heavy stockremoval is not recommended. Replace the flywheelif scoring is severe and deeper than 0.076 mm (0.003in.). Excessive stock removal can result in flywheelcracking or warpage after installation; it can alsoweaken the flywheel and interfere with proper clutchrelease.

Clean the crankshaft flange before mounting theflywheel. Dirt and grease on the flange surface maycock the flywheel causing excessive runout. Use newbolts when remounting a flywheel and secure thebolts with Mopar Lock And Seal. Tighten flywheelbolts to specified torque only. Overtightening can dis-tort the flywheel hub causing runout.

CLUTCH COVER AND DISC RUNOUTCheck the clutch disc before installation. Axial

(face) runout of a new disc should not exceed 0.50mm (0.020 in.). Measure runout about 6 mm (1/4 in.)from the outer edge of the disc facing. Obtain an-other disc if runout is excessive.

Check condition of the clutch before installation. Awarped cover or diaphragm spring will cause grab

ZJ CLUTCH DIAGNOSIS 6 - 3

and incomplete release or engagement. Be carefulwhen handling the cover and disc. Impact can distortthe cover, diaphragm spring, release fingers and thehub of the clutch disc.

Use an alignment tool when positioning the disc onthe flywheel. The tool prevents accidental misalign-ment which could result in cover distortion and discdamage.

A frequent cause of clutch cover distortion (andconsequent misalignment) is improper bolt tighten-ing. To avoid warping the cover, the bolts must tight-ened alternately (diagonal pattern) and evenly (2-3threads at a time) to specified torque.

CLUTCH HOUSING MISALIGNMENTClutch housing alignment is important to proper

clutch operation. The housing maintains alignmentbetween the crankshaft and transmission inputshaft. Misalignment can cause clutch noise, hardshifting, incomplete release and chatter. It can alsoresult in premature wear of the pilot bearing, coverrelease fingers and clutch disc. In severe cases, mis-alignment can also cause premature wear of thetransmission input shaft and front bearing.

Housing misalignment is generally caused by incor-rect seating on the engine or transmission, loosehousing bolts, missing alignment dowels, or housingdamage. Infrequently, misalignment may also becaused by housing mounting surfaces that are notcompletely parallel. Misalignment can be correctedwith shims.

INSTALLATION METHODS AND PARTS USAGEDistortion of clutch components during installation

and the use of non-standard components are addi-tional causes of clutch malfunction.

Improper clutch cover bolt tightening can distortthe cover. The usual result is clutch grab, chatterand rapid wear. Tighten the cover bolts as describedin Clutch Service section.

An improperly seated flywheel and/or clutch hous-ing are additional causes of clutch failure. Improperseating will produce misalignment and additionalclutch problems.

The use of non-standard or low quality parts willalso lead to problems and wear. Use recommendedfactory quality parts to avoid comebacks.

A cocked pilot bearing is another cause of clutchnoise, drag, hard shifting, and rapid bearing wear.Always use an alignment tool to install a new bear-ing. This practice avoids bearing misalignment dur-ing installation.

INSPECTION AND DIAGNOSIS CHARTSThe clutch inspection chart (Fig. 1) outlines items

to be checked before and during clutch installation.Use the chart as a check list to help avoid overlook-ing potential problem sources during service opera-tions.

The diagnosis charts describe common clutch prob-lems, causes and correction. Fault conditions arelisted at the top of each chart. Conditions, causes andcorrective action are outlined in the indicated col-umns. Use the charts as a guide when diagnosingfaulty clutch operation.

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Fig. 1 Clutch Inspection Points

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ZJ CLUTCH DIAGNOSIS 6 - 9

CLUTCH SERVICE

INDEX

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Clutch Cover and Disc Installation . . . . . . . . . . . . . 10Clutch Cover and Disc Removal . . . . . . . . . . . . . . 10Clutch Housing Installation . . . . . . . . . . . . . . . . . . 11Clutch Housing Removal . . . . . . . . . . . . . . . . . . . . 11Clutch Hydraulic Linkage Installation . . . . . . . . . . . 12Clutch Hydraulic Linkage Removal . . . . . . . . . . . . . 12

Clutch Pedal Installation . . . . . . . . . . . . . . . . . . . . 13Clutch Pedal Removal . . . . . . . . . . . . . . . . . . . . . . 13Flywheel Service . . . . . . . . . . . . . . . . . . . . . . . . . . 14Pilot Bearing Replacement . . . . . . . . . . . . . . . . . . 12Release Bearing Replacement . . . . . . . . . . . . . . . . 11Starter Ring Gear Service . . . . . . . . . . . . . . . . . . . 14

CLUTCH COVER AND DISC REMOVAL(1) Raise vehicle.(2) Remove transmission and clutch housing as as-

sembly (Fig. 2). Refer to Group 21 for procedures.(3) If clutch cover will be reused, mark position of

cover on flywheel with scriber, chalk, or center punch(Fig. 2).

(4) Loosen clutch cover bolts evenly and in rotationto relieve spring tension. Loosen bolts a few threadsat a time only to avoid warping cover. This is espe-cially important if cover will be reused.

(5) Remove cover bolts and remove cover and disc.

CLUTCH COVER AND DISC INSTALLATION(1) Reduce minor scratches or surface glazing on

flywheel face with 120/180 grit emery cloth. Cleanflywheel surface with Mopar brake cleaner or waxand grease remover afterward.

(2) Check runout and free operation of new clutchdisc.

(a) Install disc on transmission input shaftsplines. Be sure disc slides freely on splines. Leavedisc on splines for runout check.

(b) Measure disc runout with dial indicator. Posi-tion indicator plunger about 6 mm (1/4 in.) fromouter edge of disc facing.

(c) Rotate input shaft and note indicator reading.Disc runout should not exceed 0.5 mm (0.020 inch).Obtain another disc if runout exceeds this limit.(3) Lubricate crankshaft pilot bearing with Mopar

high temperature grease, or equivalent.(4) Insert clutch alignment tool in disc and position

disc on flywheel.(5) Verify that disc hub is positioned correctly. Side

of hub marked ‘‘Flywheel Side’’ should face flywheel(Fig. 2).

(6) Insert alignment tool or spare input shaft in pi-lot bushing and position disc on flywheel (Fig. 3).

(7) Position clutch cover over disc and on flywheel.Verify that disc and cover are aligned before proceed-ing.

(8) Install and tighten clutch cover bolts until snugbut not to specified torque.

(9) Tighten clutch cover bolts to 52 Nzm (38 ft. lbs.)

CAUTION: Tighten the clutch cover bolts evenly in astar pattern to avoid distorting the cover.

(10) Apply light coating of Mopar high temp greaseto input shaft splines and to release bearing slidesurface of front bearing retainer. Do not overlubri-cate shaft splines. This could result in greasecontamination of disc.

Fig. 2 Clutch Disc Position

Fig. 3 Clutch Disc Alignment

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(11) Install transmission-clutch housing assembly.Refer to Figure 4 for attaching bolt torques.

CLUTCH HOUSING REMOVAL(1) Raise vehicle and remove transmission and

clutch housing as assembly.(2) Remove release bearing, release lever, boot, and

lever ball stud from clutch housing (Fig. 5).(3) Remove clutch housing attaching bolts and re-

move housing from transmission (Fig. 5).

CLUTCH HOUSING INSTALLATION(1) Clean housing mounting surface of engine block

with solvent.(2) Check alignment dowels in engine block. Be

sure dowels are in good condition and properlyseated.

(3) Lubricate release bearing bore, release leverand pivot ball contact surfaces with Mopar high tem-perature grease.

(4) Transfer pivot ball stud, release lever, boot, andrelease bearing to new housing.

(5) Clean transmission and clutch housing mount-ing faces with solvent. Be sure all dirt, grease, oil areremoved completely. Surfaces must be clean to en-sure proper seating and avoid housing misalignment.

(6) Align and install clutch housing on transmis-sion. Tighten housing bolts to 33-43 Nzm (24-32 ft.lbs.) torque.

(7) Install transmission as described in Group 21.Install transmission-to-engine struts after clutchhousing has been installed. Tighten bolts attachingstruts to clutch housing first and strut-to-enginebolts last.

RELEASE BEARING REPLACEMENT(1) Remove transmission and clutch housing as an

assembly.(2) Disconnect release bearing from lever and re-

move bearing (Fig. 5).(3) Inspect bearing slide surface of transmission

front bearing retainer. Replace retainer if slide sur-face is scored, worn, or cracked.

(4) Inspect release lever and lever pivot ball stud.Be sure pivot is secure and in good condition. Be surelever is not distorted or worn. Replace release leverretainer spring if bent or damaged in any way.

(5) Lightly lubricate contact/pivot points of follow-ing parts with Mopar high temperature grease:• crankshaft pilot bearing• transmission input shaft splines

Fig. 5 Clutch Housing And Release Bearing Attachment

Fig. 4 Transmission/Clutch Housing Installation

ZJ CLUTCH SERVICE 6 - 11

• transmission bearing retainer slide surface• release lever• release lever pivot stud

(6) Install release lever and new release bearing.Be sure lever and bearing are properly secured.

(7) Install transmission and clutch housing as as-sembly.

PILOT BEARING REPLACEMENT(1) Remove transmission and clutch housing.(2) Remove clutch cover and disc.(3) Remove pilot bearing. Use blind hole puller

tools such as those included in Snap-On set CG40CBto remove bearing.

(4) Clean bearing bore with solvent and wipe drywith shop towel.

(5) Lubricate new pilot bearing with Mopar hightemperature grease.

(6) Position and start new bearing in bearing boreby hand. Note that pilot bearing has seal at oneend. Install bearing so seal is facing out and to-ward transmission.

(7) Seat pilot bearing with clutch alignment tool(Fig. 6). Keep bearing straight during installa-tion. Do not allow bearing to become cocked.Tap bearing into place until flush with edge ofbearing bore. Do not recess bearing.

(8) Install clutch cover and disc.(9) Install clutch housing and transmission as as-

sembly.(10) Install transfer case, propeller shafts, wire

harnesses, vacuum hoses, crossmembers, shift link-age and remaining components removed during ser-vice.

CLUTCH HYDRAULIC LINKAGE REMOVALThe clutch master cylinder and pedal position

switch, remote reservoir, slave cylinder, andconnecting lines are only available as a com-plete assembly. The linkage components cannotbe overhauled or serviced separately. The cylin-ders and connecting lines are sealed units.

(1) Raise vehicle.(2) Remove nuts attaching slave cylinder to clutch

housing.(3) Remove slave cylinder and clip from housing.(4) Disengage hydraulic fluid line from body clips.(5) Lower vehicle.(6) Remove retaining ring, flat washer and wave

washer that attach clutch master cylinder push rodto clutch pedal (Fig. 7).

(7) Disconnect clutch pedal position switch wires.Then slide clutch master cylinder piston rod offclutch pedal pin.

(8) Inspect condition of bushing on clutch pedalpin. Remove and replace bushing if worn or dam-aged.

(9) Verify that cap on clutch master cylinder reser-voir is tight. This is necessary to avoid undue spill-age during removal.

(10) Remove screws attaching clutch fluid reservoirto dash panel.

(11) Remove nuts attaching clutch master cylinderto stud nuts (Fig. 7).

(12) Remove both clutch cylinders, reservoir andconnecting line from vehicle.

CLUTCH HYDRAULIC LINKAGE INSTALLATION(1) Tighten cap on clutch fluid reservoir to avoid

spillage during installation.(2) Position cylinders, connecting lines and reser-

voir in vehicle.(3) Install clutch master cylinder on mounting

studs extending through dash panel (Fig. 7). Tightenattaching nuts to 23-34 Nzm (200-300 in. lbs.) torque.

(4) Position reservoir on dash panel and installreservoir screws. Tighten screws to 5 Nzm (40 in. lbs.)torque.

(5) Install replacement bushing on clutch pedal pinif necessary.

(6) Install clutch master cylinder push rod onclutch pedal pin. Secure rod with wave washer, flatwasher and retainer ring.

(7) Connect clutch pedal position switch wires.(8) Raise vehicle.(9) Insert slave cylinder push rod through clutch

housing opening and into release lever. Be sure capon end of rod is securely engaged in lever. Check thisbefore installing cylinder attaching nuts.

(10) Install and tighten slave cylinder attachingnuts to 23-34 Nzm (200-300 in. lbs.) torque.

Fig. 6 Pilot Bearing Installation

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(11) Insert clutch fluid line in body clips and lowervehicle.

CLUTCH PEDAL REMOVAL(1) Disconnect clutch pedal position switch wires.(2) Remove retaining ring, flat washer and wave

washer that secure clutch master cylinder push rodto clutch pedal pin (Fig. 8).

(3) Remove fastener that secures pedal shaft topedal support.

(4) Slide pedal shaft out left side of pedal supportand out of clutch pedal.

(5) Slide push rod off clutch pedal pin and removeclutch pedal.

(6) Remove and inspect bushings in clutch pedalshaft bore and on bushing on pedal pin. Replace anybushing that is worn or damaged.

CLUTCH PEDAL INSTALLATION(1) Lubricate pedal shaft, pedal shaft bore and all

bushings with generous quantity of Mopar multi-mileage, or high temp grease.

(2) Insert pedal pin into cylinder push rod. Thenposition clutch pedal in support.

(3) Slide pedal shaft through clutch pedal bore andbushings.

(4) Install bolt that retains pedal shaft in support.

(5) Secure push rod to pedal pin with wave washer,flat washer and retaining ring.

(6) Connect clutch pedal position switch wires.

Fig. 7 Clutch Hydraulic Linkage Components

Fig. 8 Clutch Pedal Mounting

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FLYWHEEL SERVICEInspect the flywheel whenever the clutch disc,

cover and housing are removed for service. Checkcondition of the flywheel face, hub, ring gear teeth,and flywheel bolts.

Minor scratches, burrs, or glazing on the flywheelface can be scuff sanded with 120/180 grit emerycloth. However, the flywheel should be replaced if thedisc contact surface is severely scored, heat checked,cracked, or obviously worn.

Cleanup of minor flywheel scoring should be per-formed with surface grinding equipment. Removeonly enough material to reduce scoring (approximate-ly 0.001 - 0.003 in. maximum).

Heavy stock removal from the flywheel face isnot recommended. Replace the flywheel if scor-ing is severe and deeper than 0.076 mm (0.003in.). Excessive stock removal can result in fly-wheel cracking or warpage after installation. Itcan also weaken the flywheel and interferewith proper clutch release.

Check flywheel runout if misalignment is sus-pected. Runout should not exceed 0.08 mm (0.003in.). Measure runout at the outer edge of the fly-wheel face with a dial indicator. Mount the dial indi-cator on a stud installed in place of one of theflywheel attaching bolts.

Clean the crankshaft flange before mounting theflywheel. Dirt and grease on the flange surface maycock the flywheel causing excessive runout.

Check condition of the flywheel hub and attachingbolts. Replace the flywheel if the hub exhibits cracksin the area of the attaching bolt holes.

Install new attaching bolts whenever the flywheelis replaced and use Mopar Lock N’ Seal, or Loctite242 on replacement bolt threads.

Recommended flywheel bolt torque is 142 Nzm (105ft. lbs.).

STARTER RING GEAR SERVICEInspect the teeth on the starter ring gear. If the

teeth are worn or damaged, the flywheel shouldbe replaced as an assembly. This is the recom-mended and preferred method of repair.

In cases where a new flywheel is not readilyavailable, a replacement ring gear can be in-stalled. However, the following precautionsmust be observed to avoid damaging the fly-wheel and replacement gear.

Ring Gear Replacement(1) Mark position of the old gear for alignment ref-

erence on the flywheel. Use a scriber for this pur-pose.

(2) Wear protective goggles or approved safetyglasses. Also wear heat resistent gloves when han-dling a heated ring gear.

(3) Remove the old gear by cutting most of the waythrough it (at one point) with an abrasive cut-offwheel. Then complete removal with a cold chisel orpunch.

(4) The ring gear is a shrink fit on the flywheel.This means the gear must be expanded by heating inorder to install it. The method of heating and ex-panding the gear is extremely important. Everysurface of the gear must be heated at the same timeto produce uniform expansion. An oven or similar en-closed heating device must be used. Temperature re-quired for uniform expansion is 325-350° F. Heatingtime is approximately 30 minutes.

CAUTION: Never use an oxy/acetylene torch to re-move the old gear, or to heat and expand a newgear. The high temperature of the torch flame willcause localized heating and damage the flywheel. Inaddition, using the torch to heat a replacement gearwill cause uneven heating and expansion. The torchflame will also anneal the gear teeth resulting inrapid wear and damage after installation.

(5) The heated gear must be installed evenly toavoid misalignment or distortion. A shop press andsuitable press plates should be used to install thegear if at all possible.

(6) Be sure to wear eye and hand protection. Heatresistent gloves and safety goggles are needed forpersonal safety. Use metal tongs, vise grips, or simi-lar tools to handle the hot gear during installation.

(7) Allow the flywheel and ring gear to cool downbefore installation. Set the assembly on a workbenchand let it cool in normal shop air.

CAUTION: Never use water, or compressed air tocool the new ring gear. The rapid cooling producedby water or compressed air can distort, or crack thering gear and flywheel.

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