New Holland T8010 Manual page 460

Section 25 - Four-Wheel Drive Front Axle - Chapter 5
When the axle hits a medium-sized bump, oil will be forced from the piston side through the lockout valve (4) and
check (11) to the rod side of the cylinder and through lock out valve (3) to orifice (9) and relief valve (10). Since
orifice (9) will not handle this much flow relief valve (10) will open allowing the oil to pass to the accumulator. The
accumulator absorbs the shock to the axle. No oil passes to tank, it is stopped at check valve (14), the check in the
unload valve (5), and relief valve (7).
To return the axle to its original position the additional pressure now in the accumulator will force oil flow back to the
piston end of the cylinder through check valve (8). Oil displaced from the rod end of the cylinder will flow back
through orifice (12) and lockout valve (4) back to the piston end of the cylinder.
If the axle hits a large bump oil will be forced from the piston side through the lockout valve (4) and check (11) to the
rod side of the cylinder and through lock out valve (3) to orifice (9) and relief valve (10). Since orifice (9) will not
handle this much flow relief valve (10) will open allowing the oil to pass to the accumulator. With the volume of oil
now too great for the accumulator to absorb, excess oil will pass through lock out valve (4) then through relief valve
(7) to tank.
Returning the axle to its original position will require additional oil to the system since some was lost to sump.
When the potentiometer signals the controller that the axle has moved out of the mid point band for more than 0.1
second the controller will energize the raise solenoid (1) and maintain current to both lockout valves (3 and 4). PFC
oil will be directed to the signal line, through check valve (14), check (8), through the energized lockout solenoid (3)
to the piston end of the cylinder. Oil from the rod end will also flow through the orifice (12) through lockout valve (4)
into the piston end of the cylinder.
To lower the front of the tractor the lower solenoid (2) is energized along with the two lockout valves (3 and 4). This
allows PFC pressure to flow through the solenoid (2) to open the unload valve (5). Oil from the piston side of the
cylinder will flow through the check in lockout valve (4) with some going to tank through the unloading valve and
some through check (11) and orifice (12) to fill the void in the rod side of the cylinder. Lowering the front of the
tractor will normally only occur during calibration or if weight is removed from the front of the tractor.
Specifications:
Lockout solenoid resistance 5.6 ohms.
Raise and Lower solenoids resistance 10 ohms.
Accumulators come pre-charged to 420 to 450 PSI with dry nitrogen and are not serviceable.
25-5-5