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Chapter 21
End of Chapter Review Questions Answer Key
1. Technician A says that most ECATs will not shift when first started up under extreme
cold conditions. Technician B says that extremely cold transmission fluid can create high
enough transmission oil pressure to trip the main pressure relief valve. Who is correct?
2. What is the J1939 source address of the transmission ECU?
3. When performing a resistance key-off test on J1939 bus accessing a three-pin bus
connector, which terminal socket designation indicates CAN Low?
4. How many reluctor teeth are on a standard tailshaft vehicle speed sensor (VSS) used to
signal road speed?
5. Which of the following ECATs uses a single planetary gearset?
6. When using a DMM to perform a key-off resistance test across terminal designations D
and C on a J1939 diagnostic connector, a reading of 120 ohms is produced. What does
this suggest?
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7. Which letter(s) in the transmission identification code would indicate that an Allison WT
was equipped with a dropbox?
8. How many clutch assemblies are used in the basic WT gearbox?
9. How many planetary gearsets are used in the basic WT gearbox?
10. Which of the following is responsible for converting a command electrical signal into
mechanical movement in Allison electronic transmissions?
11. What drives the sun gear in the Allison WT P1 planetary gearset?
12. What force is used to effect the mechanical movement of clutch pistons in a WT?
13. In which of the planetary gearsets in the WT does the reversal of input rotation take
place?
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14. Which of the following components is splined to the WT output shaft?
15. Which of the following is required to connect the WT to the chassis electrical system?
16. When first put into service, for how many starts is the WT AutoDetect enabled?
17. In which of the following applications would WT electronics require a dedicated TPS
signal?
18. Technician A says that WT electronics will always display the most recently logged
trouble code first. Technician B says that WT electronics are capable of logging up to
five active codes. Who is correct?
19. Technician A says that WT trouble codes can only be accessed by using a DDR with the
appropriate software card or cartridge. Technician B says that the shift selector
mechanism may be used to read active codes. Who is correct?
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20. Technician A says that to put a WT into reverse, clutches C3 and C5 must be applied.
Technician B says that in reverse range, the P3 pinion carrier becomes the reverse output.
Who is correct?
21. How many gear speed ratios are used in a Caterpillar CX31 transmission?
22. How many gear speed ratios are used in a Caterpillar CX35 transmission?
23. What is used to hold planetary members in CX transmissions?
24. What is the main pressure value used in Caterpillar CX transmissions?
25. Which of the following best describes the counter-rotating torque converter used in a
Voith DIWA transmission?
26. Technician A says that the planetary gearset in the output module provides an overdrive
option. Technician B says that the TC10 twin countershafts always rotate when the
turbine shaft rotates. Who is correct?
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27. How many rotating clutches are there in a TC10 transmission?
28. Which of the following must occur to engage the torque converter clutch (TCC) in a
TC10 transmission?
29. When the TCC is in fourth range, which of the following clutches must be engaged?
30. Which of the following check methods is recommended by Allison to ensure the oil level
is correct at operating temperature after a fluid change?