Final gear Disassembly and Reassembly

Final gear disassembly

1.      Remove the nuts and bolts holding the bearing housing.

2.      Remove the ring gear assembly and thrust washer from the final gear case.

3. Remove the self-locking nut from drive pinion by using the holding tool (special tool) and remove the coupling.

1. Middle and final gear holding tool

4. Remove the drive pinion bearing retainer with the retainer remover (special tool).

CAUTION: The drive pinion bearing retainer nut is left hand threads. Turn the retainer nut clockwise to loosen.

1. Drive pinion bearing retainer remover

5. Remove the drive pinion and bearing with the slide hammer and adapter (special tool).

CAUTION: This drive pinion removal should be performed only if gearing replacement is necessary. Do not re-use bearings or races after removal.

1. Slide hammer 2. Crank installer adapter

6. Remove the guide coller, oil seal, and roller bearing from the main housing by using the press tool No. 1 (special tool) and a press. Use an appropriate supports for the main housing during this operation. The roller bearing may be reused if undamaged. Do not re-use oil seal.

7. Rear drive pinion roller bearing; removal of this bearing is difficult and seldom necessary. Heat the bare housing to 150°C (302°F). Use an appropriately shaped punch to remove the roller bearing outer race. Remove the inner race from the drive pinion-

Final gear reassembly

1. Install the new rear drive pinion roller bearing. Heat the bare bearing to 150°C (302°F) and use an appropriately adapter to install the roller bearing outer race. Install the inner race onto the drive pinion.

2. Using the press tool No. 2 (special tool) and a press, install the guide coller, new oil seal, and roller bearing into the main housing in that order.

NOTE: The removed roller bearing can be used if undamaged; however, we recommend replacement with a new one.

3. Final drive/ring gear positioning

NOTE: When the following part(s) is replaced with new one(s), gear positioning is necessary:

a.    Final gear

b.    Ring gear bearing housing

c.    Bearing(s)

a. The shim thickness "A" necessary for the drive pinion gear positioning can be calculated from the informations found on the final gear case and on the drive gear end.

To fined shim thickness "A" use the formula:

A = a - b

Where: a =a numeral (usually a decimal number) on the gear near the tooth and either added to or detracted from the nominal size "84". b =a numeral on the gear case appearing as a whole figure (ie. 83.50).

Example:

1)     If the pinion gear is marked "+01" ....: "a" is 84.01.

2)      If the gear case is marked "83.50".

A = 84.01 - 83.50

A = 0.51

Then the necessary shim thickness is 0.51 mm.

Shim sizes are supplied in the following thicknesses:

0.15 mm, 0.30 mm, 0.40 mm, 0.50 mm, 0.60 mm.

Because the shims can only be selected in 0.05 mm increments the following

chart should be used when encountering last digits that are not 5 or zero (0):

Last digits	Rounding
0, 1.2	0
3, 4, 5, 6. 7	5
8, 9	10

Shim thickness: 0.50 mm

b. The shim thickness "B" necessary for the ring gear positioning can be calculated from the informations found on the final gear case, ring gear, and bearing.

To find shim thickness "B" use the formula:

B = c + d-(e + f)

Where:

c = a numeral on the gear case appearing as a whole figure (ie. 45.52)

d = a numeral (usually a decimal number) on the outside of the ring gear bearing housing and added to the nominal size "3".

e = a numeral (usually a decimal number) on the inside of the ring gear and; either added to or detracted from the nominal size "35.40".

f = a bearing thickness (considered constant)

Distance "f" = 13.00 mm

Example:

1)      If the gear case is marked "45.52".

2)      If the ring gear bearing housing is marked "35"....."d" is 3.35.

3)     If the ring gear is marked "+01" .....

"e" is 35.40 + 0.01 = 35.41.

4)      "f" is 13.00.

B = c + d-(e + f)

B = 45.52 + 3.35 - (35.41 + 13.00)

8 = 48.87 - (48.41)

B = 0.46

Then the necessary shim thickness is 0.41 mm.

NOTE:  Use the chart for the drive pinion shim to select the ring gear shim size.

Shim thickness: 0.40 mm

4. Install the drive pinion gear with the proper size of shim(s) and secure it with the bearing retainer nut with the drive pinion bearing retainer remover (special tool).

NOTE: The bearing retainer nut is left hand threads;

turn the nut to counterclockwise to tighten.

Tightening torque: 110 Nm (11.0 mkg, 80 ftlb)

5. Install the ring gear assembly without the thrust washer. Adjust the gear lash (refer to "Gear lash check and adjustment").

6.      Place four pieces of "PLASTIGAGE" between the originally fitted thrust washer and ring gear.

7.      Install the gear case onto the ring gear assembly and tighten the nuts and bolts with the specified torque.

Tightening torque:

Bolt/Nut: 23 Nm (2.3 mkg, 17 ftlb)

NOTE:  Do not turn the drive pinion/ring gear when measuring clearance with "PLASTIGAGE".

8. Remove the ring gear assembly and determine the clearance by measuring the width of the flattened "PLASTIGAGE".

Ring gear thrust clearance:

0.1 - 0.2 mm (0.004 - 0.0078 in)

1. PLASTIGAGE

9. If the clearance exceeds the specification above, replace the thrust washer to obtain the proper clearance.