Model MA TOW Tractor. Manual - part 15

Chapter 3: Overhaul

Dec. 1995                     Section 3-4                        p. 1

IV.

DRIVE AXLE

If the tractor has been properly lubricated, maintained, and operated and has not experienced damage
to the drive axle, the drive axle will provide many hours of service without an overhaul. Should over-
haul be required, or suspected of being required, follow the procedure below:

A.

REDUCTION GEAR BOX

1.

Removal:

It is not necessary to remove the drive axle from the tractor to conduct disassembly and/or
overhaul of the reduction gear case. Disassembly of the reduction gear case is therefore

accomplished as follows:

(a)

Disconnect the rear section of the drive shaft from the drive axle input shaft flange

by removing the attachment bolts.

(b)

Drain the gear case by removing the gear case oil drain plug located at the bottom

portion of the reduction gear case.

(c)

Remove the input shaft flange from the front side of the reduction gear case by

removing the input shaft retainer nut and washer.

(d)

Remove the input shaft rear cap and gasket by removing the attachment bolts.

(e)

Remove the large snap ring retaining the input shaft rear bearing in place to the

reduction gear case cover.

(f)

Remove the reduction gear case cover by removing the retaining bolts and

loosening the cover from the case by tapping the two case positioning pins from the
case side.

(g)

Grasp the input shaft from inside the reduction gear case and extract the shaft,

together with its bearings (front and rear), from the case housing.

(h)

Remove the reduction gear from the case housing by removing the bevel pinion
bearing nut.

(i)

 Remove the reduction gear case from the drive axle by cutting the lock wire and
 removing the gear case retaining nuts and washers.

(j)

Remove the input shaft front cap and gasket from the reduction gear case by

removing the attachment bolts.

NOTE: Input shaft front cap and gasket omitted on late serial rear axles.

2.

Cleaning:

Clean the front and rear bearings on the input shaft with a suitable solvent such as

kerosene. Use of vapor degreaser is permissible in lieu of kerosene or other solvents.

Chapter 3: Overhaul

Dec. 1995                     Section 3-4                        p. 2

IV.

DRIVE AXLE

A.

REDUCTION GEAR BOX

2.

Cleaning: (cont)

NOTE: Do not clean the bearings with gasoline nor place them in a hot solution tank for

cleaning.

3.

Inspection:

At this point in the disassembly operation, all parts have been disassembled in the

reduction gear case, except for bearings, seals, and the oil filler cap and the oil breather.
Inspect all parts as follows:

(a)

Inspect the reduction gear and drive gear for wear or damage. Replace the gears if

they are pitted, galled, worn, or broken.

(b)

After cleaning, inspect the bearings and replace the bearings if they are pitted, worn,

or damaged in any way. Remove the bearings as required with a puller.

NOTE: Do not use drifts or hammers in removing bearings, as they may easily

mutilate or

distort component parts.

(c)

Clean and inspect the remaining parts of the reduction gear assembly.

(d)

Replace hexagon nuts with rounded corners with new nuts. Replace all lock washers,

oil seals and gaskets with new parts.

NOTE: Use genuine TUG Manufacturing Corporation replacement parts for

satisfactory service. For example, making gaskets or foreign material generally
leads to mechanical trouble due to variations in the thickness and compressibility of
certain materials.

4.

Assemble

Assemble the overhauled reduction gear assembly as follows:

(a)

Install new bearings and seals with a suitable press. Coat the bearings with suitable
lubricant and coat the seal contacting surfaces with grease.

(b)

Apply a non-hardening sealing compound to the input shaft flange cap contact

surface and install the cap to the reduction gear case using the four (4) attachment
bolts and new lock washers.

Reduction Gear Case Components:

(c)

Install the reduction gear case to the drive axle using the gear case retaining nuts

and washers. Lock-wire the nuts using soft iron wire.

Chapter 3: Overhaul

Dec. 1995                     Section 3-4                        p. 3

(d)

Install the reduction gear and secure the gear with the bevel pinion bearing nut, nut

lock, and bevel pinion bearing locking nut.

(e)

Install the input shaft into the gear case housing.

(f)

Apply a non-hardening sealing compound to the gear case cover contact surface and
install the cover, aligning the positioning pins of the cover into their retaining holes
on the case. Tap the case cover into the installed position.

(g)

Install the gear case cover attachment bolts and torque to specification.

(h)

Secure the input shaft in the correct position by installing the rear bearing snap ring.

(i)

Install the input shaft rear cap and new gasket using the attachment bolts and new
lock washers.

NOTE:  Input shaft front cap and gasket omitted on late serial rear axles.

(j)

Install the input shaft flange onto the shaft using the input shaft washer, nut and

cotter pin, torquing the nut to specification.

(k)

Assure the gear case oil drain plug is clean and free of any foreign matter and
install the plug into the gear case.

Unless other maintenance is to be preformed on the drive axle, fill the reduction

gear case with proper lubricant (SAE #140 in summer, #90 in winter).

B.

DRIVE AXLE

1.

Preparations:

NOTE: For overhaul of drive axle it should be removed from tractor.

(a)

Prepare drive axle for disassembly by removing tires, wheels, reduction gear case

and removing the oil plug from the bottom of the axle housing to drain out the oil.

(b)

Support axle, on suitable supports on both sides of axle assembly inboard of the

wheels and hubs.

2.

Remove Axle Shaft:

(a)

Disconnect brake lines from caliper and drain fluid into suitable container. Discard
fluid.

(b)

Remove the axle shaft cotter pin, nut and washer from the axle.

(c)

Remove the crossover line, outer brake caliper half, wheel hub and rotor, thereby

gaining access to the axle shaft oil seal retainer.

Chapter 3: Overhaul

Dec. 1995                     Section 3-4                        p. 4

IV.

DRIVE AXLE

B.

DRIVE AXLE

2.

Remove Axle Shaft: (cont)

(d)

Remove the oil seal retainer by removing the bolts lock washers holding it in place.
Because of the tight fit of the seal, it may be necessary to use a screwdriver or

chisel with small hammer and lightly tap the back edge of the seal at several points
around its periphery.

(e)

Remove the bearing retainer, gasket and shims.

NOTE:  At this point the axle shaft may be removed from the housing. The amount

of force necessary to remove the axle shaft is dependent upon the condition of the
axle; therefore, three alternative methods are offered.

(f)

Wipe the exposed axle shaft free of oil; using both hands, pull the axle shaft,

bearings and cups from the housing. If the shaft cannot be removed in this manner,
proceed to next step.

(g)

Reinstall axle shaft nut on axle. Using wooden dowel and small hammer, firmly tap

against the back side of the axle nut, driving axle shaft from housing.

CAUTION: DO NOT USE SCREWDRIVER OF METAL OBJECTS IN LIEU OF

WOODEN  DOWEL. METAL OBJECTS WILL DAMAGE THE AXLE AND NUT. DO
NOT USE EXTREME FORCE.

(h)

If axle cannot be removed as discussed above, attach axle in conventional manner.

(i)

Inspect axle bearing cage to assure that all components are removed from cage.

The axle will come out with the axle as will the outer bearing cup and the bearing
pacer collar. The inner bearing cup may be retained in the cage. This should also be
removed using a puller or similar device.

3.

Disassemble Axle Housing:

(a)

Place axle assembly in heavy vise or other heavy holding fixture.

(b)

Before disassembling, place length of pipe or suitable support, slightly smaller than

axle shaft splines, approximately two-thirds (2/3) through axle from the case side to
prevent dropping the differential assembly.

(c)

Remove bolts, nuts and washers from case and cover and remove cover half.

(d)

Remove differential and gear assembly.

(e)

Remove pipe.