Cub Cadet BIG COUNTRY 4X2, Service Manual

4 X 2 Gear Selector

27

5.19. If vacuum signals vary, check the electrical sig-

nal to the vacuum solenoid (see “Gear Selector 
Electrical System Diagnosis” section of this 
manual).  

5.20. If the electrical system is functioning properly, 

replace the suspect solenoid valve.  

NOTE: 

The most common failure modes will be 

for a solenoid valve to be stuck fully open or 
stuck fully closed.   

5.21. If the vacuum signals are correct to this point, 

but the shift wedge does not operate correctly, 
and the transmission does not have any internal 
problems, there may be one of the following 
issues:

•

The vacuum actuator may be bad.

•

There may be a vacuum leak between the vac-
uum solenoid and the vacuum actuator.   

NOTE: 

A bad vacuum actuator will seldom work 

in either direction.

5.22. To isolate a problem that lies down-stream of the 

vacuum solenoids, dead-head the gauge into 
the vacuum line that connects to the forward 
side of the vacuum actuator.   See Figure 5.22.

5.23. Start the engine, and press the “F” button on the 

dashboard.  

5.24. The vacuum should rise to 15”-22” HG. (usually 

17”-18” HG.).

NOTE: 

The “F” and “N” buttons will flash on the 

control panel in the dashboard, and the shift 
wedge will not move.  

5.25. With any other gear selected, the vacuum level 

should be 0.

Figure 5.22

Vacuum here
pulls the shift
wedge toward
forward gear 

5.26. Repeat the test on the vacuum line that con-

nects to the reverse side of the vacuum actuator.  
The results should mirror the results of the first 
test.  

5.27. If both tests work as described, the vacuum 

actuator is bad. 

DIFFERENTIAL LOCK ACTUATOR

5.28. Testing the vacuum signal to the differential lock 

actuator is a very similar procedure.  All of the 
tests upstream of the vacuum solenoids apply to 
all three solenoids.  

5.29. Because the differential lock actuator only needs 

to move in one direction, there is only one vac-
uum line leading to the actuator.  The second 
line is only a vent.

5.30. Teeing-in the gauge between the solenoid and 

the actuator should yield a vacuum reading that 
rises to 17-18 inches, and holds when the 
engine is turned off. See Figure 5.30.  

Figure 5.30

Vent line

Vacuum line

Differential lock 

              Tee-in vacuum 
                  

 actuator

               gauge here