Powershift and Automatic Transmission Testing and Service

Question 1

The first step ofa logical troubleshooting process is to gather information. List three
(3) sources of information that should be accessed.
a)
b)
c)

Answer 1

1. a) manufacturer service manuals
   b) manufacturer service bulletins
   c) operator manuals

Question 2

2. Why is talking to the operator an in1portant step in the troubleshooting process?

Answer 2

2. The operator can provide information regarding machine performance prior to the problem, the type and frequency of maintenance, recent repair work, and machine modifications.

Question 3

3. List four (4) things that should be observed while performing a visual inspection on a
powershift or automatic transmission.
a)
b)
c)
d)

Answer 3

3. Any four (4) of the following are correct.
   a) Check transmission oil level and type. Is the level too high or low? Is the correct oil being used?
   b) Check transmission oil condition. Is it foamy, milky, oxidized, or dirty?
   c) Check for oil leaks.
   d) Look for signs of overheating (for example, discoloured paint).
   e) Check for damage such as cracked transmission case, bent shift linkage, frayed or kinked oil lines or collapsed hoses.
   f) Check the transmission shift linkage to determine if the shift selector is correctly situated in each of its positions.
   g) Check transmission mounts (for example, loose or missing bolts, cracked or broken mounting brackets).
   h) Check driveline and U-joint condition.
   Look for evidence of service (grease points, filter changes or linkage adjustments).
   j) Have there been machine modifications (for example, increased machine capacity by the addition of larger ground engaging implements)?

Question 4

4. It is important to warm transmission to operating temperature before performing operational tests because shift system leakage increases significantly as oil temperature increases.
   a) true
   b) false

Answer 4

a. True

Question 5

5.   List the four (4) steps required in performing a torque converter stall test.
a)
b)
c)
d)

Answer 5

5. a) lock the service and parking brakes.
   b) select the highest possible speed range.
   c) run the engine at wide open throttle.
   d) record engine rpm.

Question 6

6. When performing a stall test, you must be careful not to:
   a) operate the machine at wide-open-throttle.
   b) select the highest possible speed range.
   c) overheat the transmission oil.
   d) apply the parking brake.

Answer 6

6. c) overheat the transmission oil.

Question 7

7. While performing a stall test, you find that engine rpm at stall is lower than the
   manufacturer’s specifications. This indicates that:
   a) the machine is functioning normally.
   b) the engine is not producing sufficient power.
   c) a transmission clutch is slipping.
   d) torque converter charge oil flow is low.

Answer 7

7. b) the engine is not producing sufficient power.

Question 8

8. List three (3) reasons for a stall speed that is higher than specification.
   a)
   b)
   c)

Answer 8

8. a) The engine is producing excessive power.
   b) There are slipping clutches in the transmission.
   c) The torque converter is cavitating.

Question 9

9. A pressure reading of55 kPa absolute (8 psi) at the transmission charging pump
   inlet is taken. You conclude that:
   a) the charging pump is cavitating.
   b) the charging pump is aerating.
   c) a transmission clutch piston is leaking.
   d) the charging pump is excessively worn.

Answer 9

9. a) the charging pump is cavitating.

Question 10

10. It is a good practice to measure clutch application pressure with the engine running at low and high idle. Low pressure readings alt low idle with normal pressure readings
    at high idle is an indication that ____________.

Answer 10

10. There is significant leakage in the clutch application circuit.

Question 11

11. Three (3) possible causes for low torque converter charge pressure are:
    a)
    b)
    c)

Answer 11

11. a) Insufficient charge pump flow.
    b) Excessive leakage in the clutch application circuit.
    c) Excessive leakage in the torque converter circuit.

Question 12

12. One possible cause for lower than normal transmission lubrication pressure in one particular speed range is excessive clutch piston leakage.
    a) true
    b) false

Answer 12

a. True

Question 13

13. A flowmeter installed in the torque converter outlet line indicates a loss of flow in in
    all speed ranges and directions. The possible cause is:
    a) excessive charging pump leakage.
    b) charging pump cavitation.
    c) excessive torque converter leakage
    d) all of the above responses are correct.

Answer 13

3. d) All of the above responses are correct.

Question 14

14. Shift point specifications are most often given in relation to:
    a)
    b)
    c)

Answer 14

14. a) governor pressure readings,
    b) output shaft speed or
    c) vehicle speedometer readings.

Question 15

15. When the ECU in electronic shift control systems with a self-diagnostic feature
    delivers a fault code when it ________________.

Answer 15

15. senses a signal from a component that is outside the range specified by its internal program.

Question 16

16. You access a fault code from an electronic shift control system that indicates that a speed sensor in the system is delivering erratic, intermittent or incorrect data. The best course of action is to:
    a) check speed sensor adjustment.
    b) replace the speed sensor.
    c) check the wiring harness for opens, shorts, or grounds.
    d) follow the repair procedure in the service manual.

Answer 16

16. d) follow the repair procedure in the service manual.

Question 17

17. List four (4) safety rules that must be followed when removing a powershift or
automatic transmission from a machine.
a)
b)
c)
d)

Answer 17

17. Any four (4) of the following are correct.
    a) Recognize and heed safety instructions from service manuals and warning decals posted on the machine.
    b) Wherever possible, park and block the machine on a level, hard surface.
    c) Do not work on a machine that is solely supported by a hoist or hydraulic jack.
    d) Be·sure to relieve all air or hydraulic pressure.
    e) All hydraulically operated components must be lowered to the ground or mechanically supported

Question 18

18. List three (3) friction disc faults that should be detected through a visual inspection:
    a)
    b)
    c)

Answer 18

18. Any three (3) of the following are correct.
    a) burrs,
    b) imbedded metal,
    c) scoring,
    d) signs ofoverheating,
    e) cracks and
    f) damaged or distorted external tangs.

Question 19

19. Disc warpage and cone are measured using:
    a) a vernier caliper.
    b) feeler gauges.
    c) an outside micrometer.
    d) an inside micrometer.

Answer 19

b. feeler gauges.

Question 20

20. List an important check to make after installing an engine mounted transmission.

Answer 20

Check crankshaft end play.