Service manual
Section 10
10-70 
Model 3606 • Origin 10/99
10.8.16 Stabil-TRAK System
The patented Stabil-TRAK system works to stabilize the 
vehicle under various conditions. The 
Owners/Operators 
Manual
 for this vehicle contains basic Stabil-TRAK infor-
mation; a copy of the 
Owners/Operators Manual
 should 
always be in the storage compartment beneath the oper-
ators seat.
The operators display panel Stabil-TRAK indicator (C, 
Fig. 10– 47, page 10-48) goes ON when the Stabil-TRAK 
system is activated.
The stabilizing system operates via interface among the 
boom proximity switch, the park, service brake and travel 
select lever switches, and five solenoid-operated valves 
on the Stabil-TRAK cylinder manifold.
The front axle frame tilt cylinder is also involved in the 
Stabil-TRAK system, but only in a passive role as hydrau-
lic fluid is cycled to accommodate Stabil-TRAK system 
operation.
In general, if there is a problem with the Stabil-TRAK sys-
tem beyond common electrical troubles, the involved 
electrical and hydraulic circuits should each be checked 
and the exact source of the problem diagnosed before 
any parts are replaced. Refer to 
Section 9 Hydraulic Sys-
tem
 in this manual for more information.
The Stabil-TRAK or rear axle lock system can only be 
activated when the boom angle is greater than forty 
degrees (40° ). Any one, any two or all three of the follow-
ing selections will activate the system:
• Engaging the parking brake switch
• Placing the travel select lever in NEUTRAL (N)
• Depressing and holding the service brake
a. Understanding the Stabil-TRAK system
The following describes the three basic modes of the pat-
ented Stabil-TRAK system. The vehicle may operate in 
any one of these three modes.
Free Pivot Mode
(Fig. 10– 82)
Figure 10– 82. Stabil-TRAK system free pivot mode.
With the boom below 40°, the Stabil-TRAK system is in 
the free pivot mode and the rear axle is allowed to pivot 
freely. The frame sway control will function normally.
Locked Mode
(Fig. 10– 83)
With the boom above 40° and
 by activating one or more 
of the following functions listed below, the Stabil-TRAK 
system is in the locked mode and the rear axle is locked 
so it is rigid with the frame.
• engaging the parking brake switch
• placing the travel select lever in NEUTRAL (N)
• depressing and holding the service brake pedal
The frame sway control will function slower than normal 
in this mode.
Figure 10– 83. Stabil-TRAK system locked mode.
Final Positioning Mode
(Fig. 10– 84)
With the boom above
 40°, the Stabil-TRAK system is 
now in the final positioning mode. In this mode the rear 
axle is unlocked and is allowed to pivot, but will respond 
SLOWLY
 to changes in terrain.
The frame sway control function will function normally in 
this mode.
IMPORTANT: Regularly check that this system is func-
tioning properly. Refer to the Stabil-Trak System Test Pro-
cedures.
Figure 10– 84. Stabil-TRAK system final positioning mode.
Stabil-TRAK
 Light
"OFF"
Below
40°
FREE
PIVOT
MODE
OS0191
Above
40°
LOCKED
MODE
Stabil-TRAK
 Light
"ON"
OS1481
Above
40°
Stabil-TRAK
 Light
"OFF"
SLOW
PIVOT
MODE
OS1491










