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Heavy Equipment Technician Period 4 > HET 4 TRANSMISSION > Flashcards

HET 4 TRANSMISSION Flashcards

1
Q

What are the three basic functions of a transmission?

A

Multiply Torque
Reverse
Neutral

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2
Q

What are the classifications of transmissions?

A 
Synchronized or non-synchronized
Single or Multiple Countershafts
Number of forward ratios/gears
Final Gear ratio - overdrive or direct
Manual or automated shift
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3
Q

If you need to find a gear ratio through multiple gear pairs, what needs to be done to the ratios?

A

Multiple

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4
Q

Input torque is 1000ft/lb, gear ratio is 2:1, what is the output torque?

A

2000ft/lb

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5
Q

What is the formula to find output speed if given input speed and a gear ratio?

A

Input Speed ÷ Gear Ratio = RPM

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6
Q

What two things does a technician need to find out everything about a manufactures transmission?

A

Model number and spec sheet

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7
Q

What are two things that should be considered before picking a transmission for a vehicle?

A

Horsepower and torque curves

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8
Q

If a transmission has a 35% ratio step between gears, does it have a smaller or larger ratio change between each gear as compared to a 20% ratio step?

A

Larger ratio changes

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9
Q

What are some transmission components?

A 
Transmission input shaft and drive gear
main shaft and gears
synchronizers
shift lever
shift rail and forks
detents
interlocked
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10
Q

Transmission input shaft is also called?

A

Clutch shaft

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11
Q

Constant mesh means?

A

when Input turns = all gears are turning

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12
Q

What are the other names for a transmission input shaft gear?

A

Transmission drive gear

Main drive gear

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13
Q

Is neutral a gear position?

A

No

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14
Q

How many gear ratios does a transmission use at the same time (USUALLY)?

A

2 gear ratios

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15
Q

Operator Complaint: Apply clutch pedal to shift and its hard to shift, grinding gears. What could be the fault?

A

Seized Pilot Bearing

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16
Q

If a pilot bearing is seized what will happen when the clutch pedal is depressed?

A

No break in path of power, shaft continues to spin, cannot shift

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17
Q

Why is end play important?

A

Allows for expansion

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18
Q

Transmissions should be running at what temperature?

A

About 100°F above ambient temp

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19
Q

Does the countershaft or mainshaft need more thrust washers?

A

Mainshaft needs more

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20
Q

What type of bearings are used to support the mainshaft?

A

Anti-Friction bearings

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21
Q

How many of the mainshaft gears are connected to the main shaft?

A

None

pg 14 190401dA

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22
Q

What is the main purpose of the thrust washers? (wear)

A

Reduce gear wear

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23
Q

How many gears are attached to the input shaft?

A

One - Drive input gear

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24
Q

What are some ways to stop a thrust washer from turning?

A

Tabs, Tangs, Snap Rings

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25
Q

What type of teeth are on the side of a transmission gear?

A

Dog Teeth

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26
Q

A blocker ring is usually made of what material?

A

Brass/Bronze

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27
Q

What is the function of the insert in a synchronizer hub?

A
  1. Holds shift collar in centered position (neutral)

2. Allow blocker ring to line up the two gears, before joining together

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28
Q

True or False:

The inserts in the blocker ring are a tight fit?

A

False

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29
Q

How are the inserts in the synchronizer hub held out?

A

Spring force

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30
Q

What is the purpose of the groves cut into the baulk ring?

A

To cut through the oil film

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31
Q

What are the 3 stages/phases of synchronizing?

A
  1. Braking/Energizing
  2. Synchronization - same RPM
  3. Engagement
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32
Q

Operator complains about grinding gears when shifting quickly. What could be the fault?

A

Damaged/Failed synchronizer

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33
Q

What is used on some pin type synchronizers to provide spring-loaded resistance?

A

Split pins

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34
Q

In a plate and disc synchronizer, where do the reaction discs spline and where do the friction discs spline?

A 
Friction Disc - Blocker assembly
Reaction Disc (plate) - Synchronizer drum
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35
Q

Three types of synchronized types?

A

Blocker
Pin Type
Plate and Disc synchronizer

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36
Q

In neutral position are the plates and discs synchronizers slipping or engaging with each other?

A

Slipping

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37
Q

How many pieces is a shift level (usually)?

A

two piece

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38
Q

What is the purpose of a spade pin in a shift level assembly?

A

To stop lever from rotating

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39
Q

What usually sits over top of the shift lever housing?

A

Protective boot

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40
Q

Operator complains that shifting is becoming difficult. The technician finds the boot is torn on the shift lever assembly, what could be the fault?

A

Contamination around moving parts in the lower lever

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41
Q

When could a shift lever slip out from gear?

A

During Acceleration or Deceleration

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42
Q

When could a shift lever Jump out from a worn detente grove?

A

When torque load is applied

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43
Q

Where is the reverse light switch located on a transmission?

A

On the shift bar housing

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44
Q

If a transmission breather clogs, what could be a result?

A

Input/Output seals fail - leak

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45
Q

Shift fork can also be called?

A

Shift yoke

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46
Q

Shift bars can also be called?

A

Yoke bars

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47
Q

What would be the purpose of a spring-loaded plunger on the first/reverse shift block?

A

Lock out device so operator does not select 1st or reverse at high speed

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48
Q

What is the purpose of an interlock?

A

To prevent operator from selecting more than one gear at once

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49
Q

Where is an interlock located?

A

in the shift rails

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50
Q

When is the torque from the engine split evenly between two countershafts?

A

When the shafts are positioned 180° apart

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51
Q

What dictates a floating mainshaft?

A

The floating mainshaft has no bearings between the mainshaft and mainshaft gears
It floats between two countershafts

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52
Q

What is an advantage of a multiple countershaft transmission?

A

smaller, lighter

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53
Q

With multiple countershafts, what type of gears can be used?

A

Smaller gears, spur gears can be used, no thrust washers

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54
Q

Why were remote auxiliary transmissions a bad idea when they had shift linkages?

A

susceptible to wear and damaged from falling objects

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55
Q

Air shift auxiliary transmissions were preferred to remote aux transmissions, why?

A

Less likely to have shift problems due to damaged or dirty mechanical linkage

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56
Q

Why is important to drain air tanks daily on a truck with an air shift auxiliary transmissions?

A

The small air lines are susceptible to water

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57
Q

With multiple countershafts, what could be done to the housing of the transmissions?

A

Lighter, Aluminum - better heat dispersion

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58
Q

How is alignment held in a multiple countershaft transmission?

A

Precise doweling

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59
Q

What are the biggest causes of failures in a transmissions?

A

Contamination - usually from servicing

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60
Q

Oil return threads are also called?

A

Wind back seal

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61
Q

What stops oil from leaking out of the transmission?

A

Wind back seal(reverse thread) and gasket under the cover

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62
Q

On a multiple countershaft transmission, all the gears are the same size on the opposite shaft, except which ones?

A

PTO gears

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63
Q

Where are the timing marks usually found on multiple counter shaft transmissions?

A

On the countershaft gears

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64
Q

What is the usual position of the transmission to remove the gearshift cover?

A

Normally Neutral

*Ford may require transmission to be in Reverse

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65
Q

Jump out and Slip out cause the transmission to go into what position?

A

Neutral

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66
Q

Jump out can be caused by worn detents or?

A

Long shifter

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67
Q

Slip out can be caused by worn detents, worn linkage or?

A

Clutching teeth are worn out or a worn fork/collar

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68
Q

What are the two types of gear teeth on sliding clutches?

A

Dove tail or straight cut

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69
Q

What gears usually use a dove tail gear tooth on the sliding clutch?

A

4th and 5th

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70
Q

Do auxiliary transmissions use helical cut gears or straight cut gear?

A

Helical gears to handle torque

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71
Q

Operator complains of a whine/squeal, what could be the cause?

A

Insufficient clearances
PTO w/out backlash
mix matched gears

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72
Q

What could cause a transmission to get stuck in gear?

A 
twisted mainshaft
worn shift tower housing
worn input shaft splines
misadjusted clutch/clutch brake
counter shaft brake
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73
Q

What are some things that should be visually inspected when there is a transmission fault?

A

Engine and Transmission mounts
Clutch system condition
driveline condition
shift mechanism operation

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74
Q

If an operator regularly coasts down hill with the clutch pedal depressed, what could be the fault they are causing?

A

Over heating

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75
Q

True or False

A vehicle being driven under 32km/h constantly will have no faults?

A

False - unless adequate coolers are used

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76
Q

What are three things that can cause a transmission to growl?

A

Broken gear teeth
Incorrect timing - will show up immediately after rebuild
Bad Bearings

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77
Q

What type of bearing(s) support a mainshaft?

A

1 friction and 1 anti-friction

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78
Q

What causes spalling on transmission gear teeth?

A

Overloading over a short period of time

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79
Q

What can cause gear clash?

A

Improperly adjusted clutch
damaged clutch brake
seized pilot bearing
damaged splines on shaft

80
Q

A gear rattle can be cause by?

A

A rough running engine

81
Q

True or False.

Frosted gears should be replaced immediately?

A

False - normal wear

82
Q

True or False

Initial pitting is mild, usually 0.030” depth?

A

True

83
Q

Auxiliary section can have how many speed options?

A

2,3 or 4 speed

84
Q

On a non-selective mainshaft, what type of washers are used?

A

non-selective center and outer washers

85
Q

On a selective gear design mainshaft what type of washers are used?

A

Non-selective inner washers

Selective outer washers

86
Q

What is used to measure clearance between gears on a selective mainshaft?

A

feeler blades

87
Q

Where would a selective washer be found on a NON-selective mainshaft assembly?

A

For reverse gear

88
Q

How many groves are on a selective mainshaft?

A

3 groves

89
Q

Chassis air supply pressure is at a minimum of?

A

90 PSI

90
Q

What is the final check on a transmission overhaul?

A

Road test - Leak check

91
Q

A green or blue plugs might be an indication of what in the transmission?

A

Synthetic oil

92
Q

After refiling a transmission with oil, when should oil level be rechecked?

A

After letting the engine run for a short period to fill the cooler and after the road test

93
Q

How large should a buffer zone be around a diesel electric hybrid?

A

1 m all around

94
Q

Who can repair hybrid vehicles?

A

Trained/certified personnel

95
Q

A “00” glove class is good to what voltage rating?

A

0.5kV

96
Q

A “4” glove class is good to what voltage rating?

A

36.0kV

97
Q

What must be worn over insulated rubber gloves when working with high voltage?

A

Leather protectors

98
Q

How often should protective gloves be checked?

A

Every use

99
Q

What air pressure is needed to activate the splitter cylinder?

A

58-63 PSI

100
Q

Upstream from the air filter/regulator, what should air pressure be (minimum)?

A

90 PSI

101
Q

How low does the voltage need to be before working on High voltage system?

A

Below 30 volts

102
Q

How is gas charge from an accumulator vented?

A

Connect a proper venting tool

103
Q

How many groves are on a non-selective main shaft?

A

3 groves

104
Q

An auxiliary transmission is shifted mechanically or with air?

A

Air

105
Q

If a 5 speed transmission has a 2 range auxiliary how many speeds are available?

A

10 speed

106
Q

Why is a transmission with 20 gears usually called an 18 speed?

A

Most operators don’t use the lowest two gears

107
Q

The larger air switch on a gear shift is used to shift what?

A

Range

108
Q

The smaller air switch on the gear shift is used to switch?

A

Spliiter

109
Q

What should be used when heating bearings to find the correct temperature?

A

Temp pen - wax

110
Q

How much ratio change is created with a splitter?

A

15-20%

111
Q

A deep reduction gives what in the starting gear?

A

A lower than normal starting gear

112
Q

A force lube ring can also be called?

A

A halo tube

113
Q

Why are lithium batteries preferred in hybrids?

A

They can handle constant drain and fill

114
Q

What does a reduced duty cycle do?

A

Saves on fuel, better fuel economy

115
Q

How is output torque calculated?

A

Input torque x final gear ratio

116
Q

What is the purpose of a bevel on a sliding clutch?

A

To ease the engagement process and reduce gear clash during engagement

117
Q

If a cooler is forced to go over relief, what is created?

A

Heat

118
Q

What type of oil coolers are used on transmissions?

A

Oil to Coolant

119
Q

On an integral oil pump in a transmission what type of filters are used?

A

Screen - Magnets in case

120
Q

How are hybrid vehicles classified?

A

Mild hybrids and full hybrids

121
Q

What do mild hybrids not do for a vehicle?

A

Propel the vehicle without an input from the engine

122
Q

What does a full hybrid vehicle do for the vehicle?

A

Take off assist, acceleration, propel the vehicle

123
Q

What are the two types of hybrid architectures?

A

Series and Parallel

124
Q

True or False

In a series hybrid the engine never directly powers the vehicle?

A

True

125
Q

In an AC or DC drive electric haul truck what is the common hybrid application?

A

(Series) Diesel electric - engine powers a generator, that supplies power to a battery that powers wheel motors

126
Q

What is a common commercial truck hybrid?

A

Diesel electric parallel hybrid

127
Q

The electric components of a hybrid include (3)?

A

Motor/Generator
Inverter
Power Electronics Carrier PEC

128
Q

What type of motor/generator is used in a diesel parallel electric hybrid?

A

Brushless permanent magnet induction motor

129
Q

What is it called when generator charges the batteries?

A

Regenerative braking

130
Q

How many phases does the ac power need to be to operate the motor?

A

Three-phase

131
Q

What are the three ways hybrids can be propelled?

A

Electric only
Diesel electric
Diesel only

132
Q

What is the diesel engine doing while the hybrid is using electric only mode?

A

Idling

133
Q

True or False

Diesel electric mode is “parallel”?

A

True

134
Q

True/False

During highway cruise speed, the generator recharges the batteries?

A

False

135
Q

When are the batteries charged on a diesel electric hybrid?

A

During braking or coasting

136
Q

What components are apart of a hydraulic launch assist?

A

Transfer Case
Hydraulic Pump
Accumulators
Reservoir

137
Q

At what speed will the hydraulic launch assist disengage?

A

Vehicle speed exceeds 40 km/h

138
Q

A vehicle with HLA: the operator wants to coast. What must an operator due to bypass the HLA assist in slowing the vehicle?

A

Slightly depress the accelerator 10%

139
Q

What colour are high voltage cables?

A

Orange

140
Q

In a four speed aux section, high range and high splitter provide what type of drive?

A

Direct Drive

141
Q

What is a synchronizer used for in an aux section of the transmission?

A

For range shift

142
Q

Block synchronizers are used on what type of vehicle?

A

Light duty - automotive

143
Q

Slip out into neutral can happen when what teeth are worn?

A

Clutching teeth

144
Q

What could cause slow/no shifts?

A

Hydraulic lock on range shifter

145
Q

Deep reduction can also be called?

A

Low-low

146
Q

What are the speed sensors on an automated transmission used for?

A

The help synchronize shifts

147
Q

What is the purpose of a start enable relay?

A

Automated transmission, verifies trans is in netural

148
Q

When “D, Drive” is selected what gear is the transmission going to begin operation in?

A

Default

149
Q

Describe torque locked gears?

A

Too much torque between the sliding clutches and the gears for the gear motor to move the shift collar to the neutral position

150
Q

The gear shift knob is called what in a transmission with an auxiliary?

A

Master air control valve

151
Q

How many clutches are in the auxiliary two speed?

A

One sliding clutch

152
Q

In a semi-automated transmission, what gears become auto?

A

18th HI and LO

153
Q

How many clutches are in a auxiliary four speed?

A

Two sliding clutches

154
Q

The top 2 solenoid valve is connected to what components?

A

Splitter cylinder
Air regulator
Range cylinder

155
Q

A splitter cylinder is exhausting constantly, what could be the fault?

A

Cylinder seals have failed

156
Q

Where does air from the air regulator go to?

A

Splitter cylinder and Range cylinder

157
Q

Why would suppliers give a silicon based lubricant in a seal kit?

A

Petroleum products could swell the seals

158
Q

If a slave cylinder is continuously exhausting air where could the fault be?

A

Range cylinder

159
Q

What is the normal position of the splitter?

A

LOW

160
Q

What keeps the actuating pin in place?

A

Spring pressure

161
Q

Where is the slave valve mounted?

A

On the transmission, inline with the shift cover

162
Q

A 15 speed in low range can be split?

A

Yes

163
Q

In a 13 speed what is the interlock in the master air control?

A

In LOW range the transmission cannot be split

164
Q

The medallion on the top of a shift knob can show a logo or?

A

A shift pattern

165
Q

If the regulator does not bring the air pressure down to 58-63 PSI, what needs to be done?

A

Replace regulator

166
Q

Does a filter become more or less efficient as it becomes more clogged?

A

More efficient

167
Q

A gear shift knob has a blue splitter switch, how many gears does the transmission have?

A

15 speed

168
Q

As a truck goes faster, should the gear ratios get smaller or larger?

A

Smaller closer to direct drive or overdrive

169
Q

Do plastic air lines or rubber coated cloth braid have a larger or small ID?

A

Rubber coated cloth braid has a larger ID compared to plastic air lines

170
Q

When can the actuating pin in the shift cover move?

A

When the trans is in neutral

171
Q

What are the two types of airlines used?

A

Plastic and rubber coated cloth braid

172
Q

If the range selector is moved UP, what range is selected?

A

High range

173
Q

How much of a gear ratio will the Range change?

A

30-40%

174
Q

The splitter gives a small gear ration change than the range, what change in percentage is normal?

A

15-20%

175
Q

What is the PSI from the air regulator on the transmission?

A

58-63PSI

176
Q

An XY shifter has how many motors?

A

2

177
Q

A supply air line is normally what colour?

A

Red

178
Q

What are airlines connected with?

A

Brass ferrules/inserts

179
Q

Is the master air control valve specific to each transmission?

A

Yes

180
Q

Is the range cylinder double acting or single acting?

A

Double acting cylinder

181
Q

True or False

The range cylinder is double acting and held in position with spring pressure?

A

False

182
Q

How is heat reduced in an ECM with a plastic case?

A

Smaller components that produces less heat

183
Q

The transmission gear selector motor is what type of motor?

A

Reversible DC motor

184
Q

What sensors are on the transmission gear selector motor and gear shifter assembly?

A

Gear position Sensor

Rail position Sensor

185
Q

What is the rail position sensor looking for?

A

Position of the shift finger

186
Q

When the power is OFF what position are the two solenoids in, in the range and splitter solenoid valve assembly?

A

Solenoids are moved back with spring pressure allowing cylinders to exhaust

187
Q

As a range and splitter solenoid valve assembly works, the operator complains the valve is exhausting whenever a shift is made, what is the fault

A

No fault. small burst of exhaust are normal

188
Q

Does a solenoid in the range and splitter solenoid valve assembly need to be energized or de-energized to allow air to go to a cylinder?

A

Energized (one at a time only)

189
Q

How many speeds sensors are used on a automated shift transmission?

A

3 sensors

190
Q

How is an inertia brake controlled?

A

Electrically

191
Q

Where is an inertia brake installed?

A

Transmission power takeoff opening

192
Q

What does HOLD position allow the operator to do?

A

manual control over gear changes

193
Q

In an automated shifting transmission, should the vehicle be allowed to coast in the neutral position?

A

NO, truck could gain too much speed for the electronic control system to handle

194
Q

The automated shift transmissions are using what type of data link?

A

J 1939

195
Q

At what speed does a J1939 communicate at?

A

250Kb/s

Heavy Equipment Technician Period 4 (13 decks)

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