Challenger Techstar CVT MT525B Series, Operators Instruction Book, Page: 69 / 248

4 . MAINTENANCE AND ADJUSTMENTS
4.19 Challenger MT500B EU
4
4.8 - FRONT AXLE ENGAGEMENT (4WD)
When 4WD is engaged, the front wheels are driven. This
function is strongly advised for field work to keep wheel
slip to a minimum.
There are two modes of 4WD operation:
- automatic mode,
- manual mode.
IMPORTANT: To avoid damaging the front axle, it must
be disengaged for road use.
• Automatic mode:
At tractor start-up, 4WD in automatic mode.
To engage 4WD, press the engagement switch (1 Fig. 30).
The corresponding instrument panel engaged indicator
light comes on (2 Fig. 30) and the 4WD automatic mode
symbol appears on the digital display (3 Fig. 30).
When this mode is activated, 4WD is automatically disen-
gaged at speeds exceeding 14 kph. When the speed drops
below 10 kph, 4WD is automatically re-engaged.
• Manual mode:
To activate manual mode:
To exit the automatic mode and enter the manual mode,
press and hold the 4WD switch for at least 2 seconds.
When in the manual mode, the 4WD is engaged at all
times, independent of ground speed.
A single press of the 4WD switch will disengage 4WD.
Pressing the 4WD switch again will re-engage 4WD.
The following 4WD conditions are normal operation:
A. If both brake pedals are depressed 4WD will engage to
provide 4-wheel braking, regardless of ground speed.
When the brake pedals are released, 4WD is automati-
cally disengaged.
B. The 4WD will engage whenever the differential lock is
engaged.
4.9 - DIFFERENTIAL LOCK
The rear axle differential lock is used to prevent the rear
wheels from slipping in relation to one another and thus
limits tractor wheel slip during field work.
IMPORTANT: During field manoeuvres, turning is diffi-
cult with the differentials locked engaged. For this rea-
son it must be disengaged to carry out manoeuvres.
Fig. 31: To engage the differential lock, press the engage-
ment switch (1). When the switch is pressed, 4WD is si-
multaneously engaged, and the differential lock and 4WD
instrument panel indicator lights (2 and 3 respectivaly)
come on.
To disengage the differential lock, press the switch (1)
again.
IMPORTANT: Disengaging the differential lock does not
disengage the front axle.
• Automatic engagement and disengagement of the dif-
ferential lock:
This function is permanently on and ensures engagement
and disengagement of the differential lock when the link-
age control is activated (e.g.: when turning at headlands).
Thus when the linkage lifting control is activated, the differ-
ential lock is disengaged. Then when the linkage lowering
control is reactivated, the differential lock is engaged auto-
matically.
IMPORTANT: For mechanical reasons do no engage the
differential lock when a wheel is slipping.
NOTE: Any use of the brakes cancels the differential
lock. Press the switch (1 Fig. 31) again to re-engage the
differential locks. If the tractor is fitted with radar, trac-
tor wheel slip can be controlled (see paragraph 4.5.10
“Using the DOT MATRIX screen”).
Z3A-1304-11-04
KPH
A
Z3A-1321-11-04
Z3A-1042-09-04
Fig. 30
1
2
3
Z3A-1305-11-04
Z3A-1042-09-04
Fig. 31
1
2 3