2-4 Brake Drum, Reverse Clutch & 3-4 Clutch: Reassembly

Reverse Clutch

CAUTION: Reverse clutch piston seal may be damaged during installation. Carefully install reverse clutch piston by pushing evenly around circumference.
1. Apply ATF to all parts. Install inner and outer seals on pistons. Install reverse clutch piston into 2-4 brake drum. Install piston return spring and reverse return stopper to reverse position.
CAUTION: Depress the piston return spring only enough to install the snap ring.
2. Compress spring and install snap ring and SSTs to the 2-4 brake drum. See Fig 1. Compress the piston return spring. Install the snap ring. Remove SSTs. Install the dish plate. Install drive and driven plates in alternate order, beginning with driven plate. Install retaining plate and snap ring. See Fig 2.
3. Measure the reverse clutch clearance. Install the reverse clutch into the end cover, and set the dial indicator. Secure the reverse clutch by lightly pressing down with a press or similar tool. Apply 57-63 psi (4.0-4.5 kg/cm² ) of compressed air to the reverse clutch fluid passage and let the reverse clutch piston stroke 3 times. See Figure.
4. Apply 57-63 psi (4.0-4.5 kg/cm² ) of compressed air to operate reverse clutch piston. Using dial indicator, measure piston stroke. See Fig 6. Read the value when the indicator of the dial gauge stops. Release the compressed air and read dial indicator when the reverse clutch piston is not operating. Calculate the reverse clutch clearance according to the following formula: First value - second value = reverse clutch clearance.
5. Measure the clearances at four locations (90 degrees apart) repeating step  4. Verify the average value is within specification. Reverse clutch clearance should be 0.039-0.051" (1.00-1.30 mm). If not within specification, remove the snap ring and measure its thickness. Add the thickness to the average value calculated, and select snap ring whose range includes the value. See REVERSE CLUTCH SNAP RING SIZES  table.
6. Install snap ring. Perform step  4 to verify calculated value is within specification. Inspect the reverse clutch operation. Install the 2-4 brake drum to the end cover. Inspect operation by applying compressed air to the reverse clutch fluid passage. See Figure.
CAUTION: Seal on 3-4 clutch piston may be damaged during installation. Carefully install 3-4 clutch piston by pushing evenly around circumference.
7. 3-4 Clutch
   Install 3-4 clutch hub. Apply ATF to the circumference of the 3-4 clutch piston seal and install the piston into the 3-4 clutch drum.
CAUTION: Depress 3-4 seal plate only enough to install snap ring. Over-pressing will damage 3-4 seal plate edges.
8. Install spring and retainer assembly. Apply ATF to 3-4 seal plate and install seal plate onto 3-4 clutch drum. See Fig 3. Using Return Spring Compressor (49 0378 390), or equivalent, compress spring and retainer, and 3-4 seal plate. Install snap ring. Install drive and driven plates in alternate order, beginning with driven plate. See Fig 4 or Fig 5 . Install retaining plate.
9. Measure 3-4 clutch clearance. Install 3-4 clutch in end cover. Set dial gauge. Place 3-4 clutch on press and secure with light pressure. Apply 57-63 psi (4.0-4.4 kg/cm² ) of compressed air to 3-4 clutch fluid passage and allow 3-4 clutch piston to stroke 3 times. See Figure.
10. Using dial indicator, measure piston stroke. See Fig 7. Apply compressed air and operate 3-4 clutch piston. Read value when indicator of dial gauge stops. Released compressed air. Read dial gauge when 3-4 clutch piston is not operating. Subtract second value from first value to obtain 3-4 clutch clearance value.
11. Repeat step  10 at 4 locations (90 degrees apart). Ensure average value is within specification. See 3-4 CLUTCH SNAP RING SIZES  table. If clearance is not within specification, remove snap ring and measure thickness. Add snap ring thickness to average reverse clutch clearance. Select appropriate snap ring to obtain proper clearance.
12. Install 3-4 clutch drum to end cover. Apply 57-63 psi (4.0-4.5 kg/cm² ) of compressed air to 3-4 clutch fluid passage. Ensure air flow is present. Install 3-4 clutch component to 2-4 brake drum. Apply petroleum jelly to bearing, and secure onto 3-4 clutch component.
13. Install 3-4 clutch hub. Apply petroleum jelly to bearing, and secure onto 3-4 clutch hub. Install rear sun gear plate onto 2-4 brake drum. Install snap ring.

Fig 1: Installing SSTs To 2-4 Brake Drum

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Fig 2: Installing 2-4 Brake Drum Components

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Fig 3: Identifying 3-4 Clutch Drum Component Installation Order

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Fig 4: Installing Drive Plates With Part Number FN11 19370

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Fig 5: Installing Drive Plates With Part Number FNE1 19370

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Fig 6: Measuring Reverse Clutch Piston Stroke

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Fig 7: Measuring 3-4 Clutch Piston Stroke

Courtesy of MAZDA MOTORS CORP.