SECTION 7 - DRIVE TRAIN

7.1 HYDRO TRANSMISSION TROUBLESHOOTING

The following troubleshooting chart is to be used to isolate hydro transmission problems and give possible causes and corrective action responses.

The troubleshooting key is generic and can be used for several types of transmissions. Use only those possible causes and corrective actions that apply to the unit.

TROUBLE

POSSIBLE CAUSES

CORRECTIVE ACTION

 

(Refer to Key Below)

 

 

 

 

Axles Will Not Turn

1, 7, 8, 12, 16, 18, 28, 32, 38, 42

repair or replace

 

 

 

Difficult Starting

1, 6, 7, 8, 12, 16, 25, 26, 28, 38, 42

repair or replace

 

 

 

Erratic Running

1, 4, 6, 7, 8, 12, 18, 25, 26, 28, 42, 55

repair or replace

 

 

 

Jerky When Starting

1, 4, 7, 8, 12, 18, 28, 38

 

 

 

 

Jumps Out of Gear

N/A

repair or replace

 

 

 

Knocking

4, 8, 12, 18, 28, 37, 42

repair or replace

 

 

 

Loss of Power or System

4, 12, 18, 28, 37, 42

 

 

 

 

Noisy

4, 12, 18, 26, 28, 32, 37, 42

repair or replace

 

 

 

Oil Leakage

4, 22, 51, 16

repair or replace

 

 

 

Operates Hot

4, 16, 28, 32, 35, 42

 

 

 

 

Operates in One Direction Only

1, 8, 12, 30, 46

 

 

 

 

Pump Failure

4, 12, 37

repair or replace

 

 

 

Speed Loss Under Load

1, 6, 11, 28, 37, 51

repair or replace

 

 

 

Speed Loss Under Load

1, 4, 7, 12, 18, 28, 26

repair or replace

 

 

 

Will Not Drive

1, 7, 8, 18, 28, 37, 38, 48

 

 

 

 

Will Not Shift

 

repair or replace

 

 

 

TROUBLESHOOTING KEY

1

Inspect control linkage

22

Inspect hoses and lines for wear

43

Burrs on gearing

2

Inspect acceleration valves

23

Inspect implement relief valve

44

Gears improperly installed

3

Inspect charge check valves

24

Inspect charge pump

47

Shifting washer in backwards

4

Incorrect grade of lubricating oil

25

Bad transmission pump

48

Shifter/Brake shaft keyways damaged

5

Low cranking speed

26

Overheating

49

Unit clutch not disengaging

6

Controls not in correct operation

27

Cold running

50

Shifter stop assembled backwards

 

position

 

 

 

 

7

Belts are missing, to tight, loose or

28

Bad transmission motor

51

Improper fit of case to cover

 

glazed

 

 

 

 

8

Overload of vehicle

29

Check system pressure

52

Dowel pins not installed

9

Replacement parts damaged

30

Shift rod grooves worn

53

Differential bevel gears broken

10

Replacement parts improperly

31

Reverse chain broken

54

Spring in shifter weak or broken

 

installed

 

 

 

 

11

Improperly torqued attaching screws

32

Damaged cooling fan

55

Worn or stripped gear teeth

12

Air in hydraulic system

33

Inspect auxiliary relief valve

 

 

13

Broken shifter stop

34

Inspect cooling fan

 

 

14

Inspect charge check valves

35

Inspect transmission cooling fins

 

 

15

Inspect acceleration valves

36

Worn or damaged bearings

 

 

16

Check oil level-gear box sump or

37

Metallic pieces or foreign objects in unit

 

 

 

reservoir

 

 

 

 

17

Inspect heat exchanger

38

Inspect for loosely mounted

 

 

 

 

 

components

 

 

18

Inspect by-pass valve

39

Steering column loose or binding

 

 

19

Inspect charge pressure

40

Pressure relief valve sticking open

 

 

20

Inspect inlet filter

41

Pressure relief sticking closed

 

 

21

Inspect charge relief valve

42

Broken relief valve spring

 

 

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