TM 5-3810-289-12
Section XII. MAINTENANCE OF TRANSMISSION ASSEMBLY WHEELS AND TRACK COMPONENTS
or 4-inches slack on the lower side of the chain, with the
4-47. Transmission Assembly Inspection and
top being tight.
Service
(4) Be sure to turn both nuts of a pair the
Inspect the gears for damage and wear.
same amount (fig. 3-12) so as to keep the chain
Lubricate the shaft in accordance with the current
sprockets in correct alinement.
When correct
lubrication order. See figure 4-33.
adjustment is obtained, replace the adjusting nuts,
4-48. Track Support Rollers and Bracket Replacement
tighten the bearing bolts, and tighten the lock-nuts.
and Repair
(5) Readjust the crawler track belts for
a. General.
Check rollers for flat spots,
correct tension as described in paragraph 3-22.
cracks or other damage. Flat spots or cracks in rollers
b. Replace.
can be built up by welding. Repair dust shield welding.
(1) Remove propelling chain adjusting
b. Replacement of Upper Support Rollers.
lock-nuts and turn adjusting nuts as far as possible to
The upper idler rollers (fig. 4-34) which support the top
slack off roller chain adjustment.
of the tread belt can be removed without connecting the
(2) Select a pin link in mesh with one of
belt, as follows:
the sprockets and remove cotter pin from that link and
(1) With machine on firm level ground,
drive out.
travel it forward for a distance equal to length of machine
(3) Slide pin fully out to separate chain
so that all slack in belt is at the top.
and remove chain from sprockets. Insert cotter pin in
(2) Pry up track near roller for clearance
chain pin to prevent loss.
and insert blocking to hold tread belt clearance roller.
(4) To install roller chain, follow the
(3) Remove blank bolt. Withdraw roller
removal steps in reverse order.
shaft and remove roller.
c. Repair. To repair a defective link, follow the
(4) Installation is the reverse process of
instructions for removing the propelling chain and
the removal steps.
remove the defective link only.
c. Replacement of Lower Support Rollers.
4-50. Track Assembly Repair
Anyone or all of the lower idler rollers (fig. 4-35 the side
a. Loosen clamping bolts on tumbler shaft.
frame may be removed without taking the tread belt
b. Loosen the nuts on the track adjusting
apart by proceeding as follows:
screws at the takeup tumbler end by equal amounts.
(1) Propel onto a block of wood so block
c. Propel machine so that the damaged link is
is under tumbler nearest roller to be removed. This
in a position corresponding to ten o'clock on the driving
should allow enough sag of treads to clear roller. If not,
tumbler.
release takeup tumbler adjustment.
d. Secure the link below the faulty one to the
(2) Remove the two lower U-bolts which
driving tumbler by means of a rope and put a chock
allow roller shaft assembly to drop down.
under the belt.
(3) Installation is the reverse process of
e. Remove the keeper pins securing the track
removal steps.
link pins. If necessary, get a purchase on the upper run
4-49. Track Roller Chain Adjustment, Replacement
of the track belt with a pinch bar and remove the four link
and Repair
pins (fig. 4-36).
a. Adjustment.
f.
Fit the new link to the upper run first, and
(1) Before attempting to adjust the drive
using the pinch bar if necessary for alignment, install the
chains, loosen the track belts by means of adjusting nuts
link pins.
at the take-up tumbler end (para 3-22).
g. Fit the four keeper pins, remove rope and
(2) Take off the locknuts and loosen
packing, and readjust the tension of the track belt.
bearing bolts on drive sprocket end (fig. 3-12).
(3) Turn the adjusting nuts until there is 3-
4-44
