John Deere stx38 - Manual (Page 254)

6 - 22
3/21/97
TESTS AND ADJUSTMENTS HYDROSTATIC POWER TRAIN
TESTS AND ADJUSTMENTS
TRACTION DRIVE SYSTEM
Reason:
To ensure shift, neutral return, and brake linkages and
belt drive system maintain traction in lower 1/3 of
forward speed range up a 17° slope. To ensure that
transport (free-wheeling) valve assembly and linkage
allow tractor to be pushed when engaged and to drive
tractor when disengaged. Also, to ensure tractor
returns to neutral, engages the brake, stops tractor
within specification, and holds tractor stationary in
PARK position on a 17° slope or less.
Procedure:
NOTE: This is a six part test and adjustment
procedure:
• Test drive on 17° slope,
• Drive belt adjustment,
• Transport valve linkage adjustment
• Shift linkage adjustments,
• Brake rod adjustment,
• Repeat test drive on 17° slope.
Test Drive—
1. Test drive tractor to see if traction drive system pulls
tractor up a 17° slope in lower 1/3 of forward
range.
2. Look for a steady pull up the slope.
3. If test fails in any of the lower 1/3 range, the belt
tension must be adjusted.
4. Drive or push tractor onto a 17° slope, depress the
brake pedal and lock it in PARK position.
5. Shift lever and linkage must return-to-neutral,
park brake must hold tractor stationary on
slope, and tractor must not creep downward
once park brake is locked into position.
6. Drive tractor on dry pavement in a safe, open, and
level area at fast idle in full forward position. Apply
a “panic stop” force (no more than 50 pounds of
force)—tractor must stop within 0.9—1.5 M (3—
5 ft) and both wheels should “lock-up”, leaving
skid marks on pavement.
7. Repeat Steps 4—6 for reverse.
8. If any test fails, the brake linkage and return-to-
neutral linkage must be adjusted or components
replaced.
c
CAUTION
DO NOT engage shift lever too aggressively or
tractor may tip over backwards. while
performing the test drive on a 17° slope.
M42597
M42598