Model MA TOW Tractor. Manual - part 16

Chapter 3: Overhaul

Dec. 1995                     Section 3-4                        p. 5

4.

Pinion and Cage Assembly:

(a)

Remove reduction gear assembly as described above.

(b)

Remove the bevel pinion bearing washer; the cork oil retainer; the pinion bearing

and cup; and the bearing shim.

(c)

Remove the lockring from inner end of pinion shaft.

(d)

Using puller or similar device, pull pinion and cage from differential case.

5.

Differential and Gear Assembly:

(a)

Inspect the differential and gear assembly very carefully prior to disassembly as
follows:

(1)

Mount the carrier in a holding fixture. Wipe the lubricant from the internal
working parts and visually inspect them for damage.

(2)

Rotate the gears to see if there is any roughness which could indicate worn or
damaged bearings or chipped gear. Look carefully at the surface of the gear
teeth for any scouring, flaking, or signs of abnormal wear.

(3)

If no obvious misadjustment or damage is noted, inspect the gear contact.

(b)

If original identification marks are not clear, mark differential case halves with a

punch or chisel before disassembling, for correct alignment when reassembling.

(c)

Cut lock wire, remove cap screws and separate case halves.

(d)

Remove spider, pinions, side gears and thrust washers.

NOTE:  Gear should not be separated from flange unless it is to be replaced.

(e)

Remove rivets and separate gear and case if required.

(1)

Carefully center punch rivets in center of head.

(2)

Use drill 1/32" smaller than body of rivet to drill through head.

(3)

Press out rivets.

(f)

Remove differential bearings with bearing puller, if necessary to replace.

6.

Disassemble Pinion and Cage Assembly:

(a)

Tap pinion out of cage with soft mallet or press shaft from cage.

(b)

Remove bearings from shaft with suitable puller, if necessary.

Chapter 3: Overhaul

Dec. 1995                     Section 3-4                        p. 6

IV.

DRIVE AXLE

B.

DRIVE AXLE

7.

Clean:

(a)

Cleaning Solutions

CAUTION: DO NOT CLEAN THESE PARTS IN A HOT SOLUTION TANK OR

WITH  WATER AND ALKALINE SOLUTIONS, SUCH AS SODIUM HYDROXIDE,

ORTHOSILICATES OR PHOSPHATES. DO NOT STEAM CLEAN ASSEMBLED
DRIVE UNITS AFTER THEY HAVE BEEN REMOVED FROM THE HOUSING.

Parts having ground and polished surfaces such as gears, bearings, shafts and

collars, should be cleaned in a suitable solvent such as kerosene or diesel fuel oil.
Use of vapored degreaser is permissible in lieu of kerosene or other solvent.

(b)

Drying

Dry parts thoroughly immediately after cleaning. Use soft, clean, lintless absorbent
paper towels or wiping rags. Bearings should never be dried by spinning with
compressed air.

8.

Inspect:

It is impossible to overstress the importance of careful and thorough inspection of drive
unit parts prior to reassembly. Thorough visual inspection for indications of wear or stress,
and the replacement of such parts as are necessary will eliminate costly and avoidable
drive unit failure.  As a general rule, if there is any doubt about the condition of a part, it
should be replaced.

(a)

Inspect all bearings, cups and cones, including those not removed from parts of the

drive unit and replace if rollers or cups are pitted or damaged in any way. Remove
parts needing replacement with a suitable puller or in a press with sleeves.

CAUTION: AVOID THE USE OF DRIFTS AND HAMMERS. THEY MAY EASILY

MUTILATE OR DISTORT COMPONENT PARTS.

(b)

Inspect first reduction bevel or hypoid and second reduction spur gears for wear or
damage. Gears which are pitted, galled or worn or broken through case hardening
should be replaced.

(c)

Inspect the differential assembly for the following:

(1)

Pitted, scored or worn thrust surfaces of differential case halves, thrust
washers, spider trunnions and differential gear. Trust washers must be
replaced in sets. The use of a combination of old and new washers will result
in premature failure.

Chapter 3: Overhaul

Dec. 1995                     Section 3-4                        p. 7

(2)

Wear or damage to the differential pinion and side gear teeth. Always replace
the differential pinions and side gears in sets.

(d)

Inspect spur pinions for wear or damage to teeth.

(e)

Check end of pinion for indications of brinelling caused by worn splines. Replace the
parts if the splines of the pinion and/or thru-shaft are worn, permitting movement of
the pinion on the thrushaft.

(f)

Inspect axle shafts for indications of torsional fractures and runout. Axle shafts
should be inspected between centers to ascertain the amount of runout of the ground
surfaces.  Runout at the shaft flange and splines should not exceed .005 inch total

indicator reading.

9.

Repair

(a)

Replace all worn or damaged parts. Hex nuts with rounded corners, all lock washers,
oil seals and gaskets should be replaced at the time of overhaul.

(b)

Remove nicks, mars and burrs from machined or ground surfaces. Threads must be

clean and free to obtain accurate adjustment and correct torque. A fine mill file or
India stone is suitable for this purpose. Studs must be tight prior to reassembling the
parts.

10.

Assembling Pinion and Cage:

(a)

Press rear thrust bearing onto pinion.

(b)

Install lockring in slot on pinion behind bearing.

(c)

Install inner conical bearing and cup on pinion.

(d)

Slide spacer on pinion then slide on outer bearing.

(e)

Assemble the pinion shaft and cage.

CAUTION: FOLLOW TABLE I FOR TORQUING ALL AXLE ASSEMBLY FASTENERS.

11.

Assemble Differential and Bevel Gear:

(a)

Rivet bevel gear to case half with new rivets.

1.

If a new gear of differential case is to be used in the assembly, the rivet holes
in the gear and case should be checked for alignment and line reamed, if
necessary. The gear must be tight on the case pilot and riveted flush with the
differential case flange. Check with a .002" feeler gauge.

2.

Rivets should not be heated, but should be upset cold. When the correct rivet
and rivet set is used, the head being formed will be at least 1/8 inch larger in
diameter than the rivet hole.

Chapter 3: Overhaul

Dec. 1995                     Section 3-4                        p. 8

IV.

DRIVE AXLE

B.

DRIVE AXLE

11.

Assemble Differential and Bevel Gear:

(a)

Rivet bevel gear to case half with new rivets. (cont)

3.

The head will then be approximately the same height as the preformed head.
The formed head should not exceed 1/16 inch less than the preformed head as
excessive pressure will cause distortion of the case holes and result in gear
eccentricity.

(b)

Lubricate differential case inner walls and all component parts with axle lubricant.

(c)

Position thrust washer and side gear in bevel gear and case half assembly.

(d)

Place spider with pinions and thrust washers in position.

(e)

Install component side gear and thrust washer.

(f)

Align mating marks, position component case half and draw assembly together with

four (4) bolts or cap screws equally spaced.

(g)

Check assembly for free rotation of differential gears and correct, if necessary.

(h)

Install remaining bolts or cap screws, tighten to specified torque and thread with lock

wire.

(i)

If bearings are to be replaced, press squarely and firmly on differential case halves.

12.

Pinion and Case Assembly:

(a)

Coat cage flange contact surface with non-hardening sealing compound.

(b)

Position cage assembly over studs and tap into position with soft mallet.

13.

Install Differential Assembly:

(a)

Position differential and gear assembly in carrier half.

(b)

Coat carrier flange halves with non-hardening compound.

(c)

Place new differential carrier gasket over flange half and assemble halves using

differential carrier bolts, lock washers and nuts. Torque per Table I.

(d)

Install reduction gear case as described in Paragraph (a) .above.