jcb Mini CX - Problem Solving; Hydrostatic Transmission

Section E - Hydraulics
E-59 E-59
9803-9340-8
Problem Solving
Hydrostatic Transmission
The purpose of this section is to help you trace
transmission problems to a faulty unit (pump, motor, etc).
Once you have traced the faulty unit, refer to the
appropriate dismantling, inspecting and test instructions
given elsewhere in the manual.
1 Before you begin problem solving, read the Safety
Information at the beginning of this manual.
2 Make simple checks before removing and/or stripping
a major component.
3 Make sure that the hydraulic fluid is at correct working
temperature (50 ºC, 122 ºF).
4 Whatever the fault, check the condition of the
hydraulic fluid. Drain and replace if necessary.
5 Be sure to remove ALL contamination and if possible
identify its origin. It may be part of a component from
elsewhere in the circuit.
PROBLEM CAUSE - series 1 machines CAUSE - series 2 machines
No drive in either forward or reverse 1, 2, 6, 9, 10, 11, 12 1, 3, 6, 9, 10, 11, 12, 18, 19
Operates in one direction only 2 3, 6, 18
Poor drive performance, no tractive effort 2, 5, 6, 8, 10 4, 5, 6, 8, 10, 12, 16, 17, 18, 19, 20
Machine creeps in neutral 2, 7 16, 20
Machine will bnot move at idle but moves at max.
revs.
2 12, 16, 17, 19, 20
Hydraulic fluid is overheating 1, 4, 13, 14, 15 1, 4, 14, 15
KEY TO CAUSE REMEDY PAGE REF.
1 No oil in hydraulic system or oil level low Top-up as necessary.
K Hydraulic
System ( T 3-43)
2 Control linkage set incorrectly or faulty Adjust, repair or replace linkage as necessary.
3 No electrical supply to direction solenoids.
Solenoids or direction switch faulty
Check electrical circuit. Replace direction
switch or solenoids if faulty.
4 Charge pressure low Check charge pressure at transmission pump.
Clean or replace charge relief valve if faulty.
K Pump Pressure
Test Points - Series
1
Machines ( T E-65)
or K Pump
Pressure Test
Points - Series 2
Machines ( T E-66)
5 No or low pump output Check pump - carry out motor speed check. K Checking Motor
Speed - Series 1
Machines ( T E-63)
6 Bypass (Tow) valve open/set incorrectly Check valve has been reset after towing.
Replace relief valve and re-check.