Section VI. DRIVE GROUP

(2) Maximum wear allowed for parts is as follows:

Note. Plugs are used to

close off the normal location of

Mounting arm bushings. 0.005-0.010 inch

lubrication fittings on the ball

Mounting arm journals. 0.005-0.010 inch

sockets. If necessary, these plugs

Pivot arm pin. 0.005-0.010 inch

may be replaced with lubrication

Pivot arm bushings.

0.005--0.010 inch

fittings for external greasing of the

Tie rod and drag link balls. No set limit. Replace ball

ball sockets.

when out of round (or when plugs can no longer be set

(4) The ball sockets of the tie rods must be packed

snug against ball.

with high-quality chassis lubricant per LO 10-3930-620-

(3) Relubricate parts according to LO 10-3930-620-12.

12.

d. Reassembly. Reassemble in the reverse order

of figure 3-74.

Section VI. DRIVE GROUP

3-42. General

truck to the right may indicate the noise is in the left side

The drive unit is a double reduction, full-floating, internal

of the drive train (bull gears, jackshaft, etc.). Noise

gear drive, with drive wheels and differential assembly

heard while making a tight left turn may indicate the

supported by tapered roller bearings. The axle drive

source of the noise is in the right side of the drive train

shafts (jackshafts) are supported by double row thrust

(bull gear, jackshaft, etc.).

bearings. The differential carrier is mounted at the

(3) If noise cannot be located, raise front end

center of the drive axle housing. The ring gear is bolted

of lift truck, using a suitable lifting device, until drive

to the differential case, which in turn houses the spider

wheels are above the ground.

gears. The pinion gear is mounted on the drive motor

(4) Install blocking and remove lifting device.

armature shaft. Double reduction is obtained through the

(5) Operate the drive motor in forward and

spiral bevel ring and pinion gears and an internal tooth

reverse while varying the speed of drive wheels.

ring gear (bull gear) within each drive wheel.

(6) Listen to noise level to determine source

3-43. Drive Axle Noise

of noise.

a. Drive axle noise may originate in the drive train

(7) If source of noise cannot be located after

because of misalignment or improperly adjusted drive

performing steps (2) through (6), a complete

train components (e.g. alinement of the drive axle and

disassembly and inspection of each component will have

drive motor, ring and pinion gear adjustments).

The

to be performed.

drive train should be disassembled just far enough to

Note.

After

each

visual

remedy or reduce noise level. Parts should be

reassembled at the lowest noise level. The following

check

and

each

mechanical

visual and operational checks and adjustments are

adjustment. perform an operational

designed to detect, reduce, and / or eliminate drive axle

check of drive motor to determine if

noise:

noise level has been reduced or

(1) Visually check differential oil level and

eliminated.

insure that the specified lubricant is being used in

(8) Readjust wheel bearing adjusting nut by

differential. (LO 10-3930-620-12.)

loosening adjusting nut and torquing nut to 50 foot-

(2) Operate lift truck in forward and reverse

pounds while rotating wheel six times in each direction.

gears for a short period of time under the following

(9) Loosen adjusting nut between 30 degrees

conditions: 1) full acceleration, 2) coasting, and 3) tight

minimum) and 60 degrees (maximum) to allow insertion

left and right turns. Note any noise in drive train while

of cotter pin.

operating lift truck under these conditions and then refer

(10) Install cotter pin but do not secure.

to steps (a) through (c) to aid in identifying cause of

(11) drive motor and listen to noise level.

noise.

(12) If noise level is unchanged, set torque

(a) Noise from the drive train during full

wrench to a different value and torque adjusting nut.

acceleration and not heard during coasting may indicate

(13) Operate drive motor and listen to noise

misalignment of the drive train components, such as

level. Insure that adjusting nut is torqued to the value that

between the drive axle and drive motor.

provides the lowest noise level.

(b) Noise heard while the lift truck is

(14) After adjusting wheel bearings to lowest

coasting and not heard during full acceleration may

noise level, measure the backlash between the bull

indicate worn parts (e.g. worn bearings) or excessive

play between parts (e.g. ring and pinion gear).

3-87