190303E

Question 1

What type of braking system is a hydraulic retarder?

Answer 1

It is a supplementary or auxiliary braking system

Question 2

Can a hydraulic retarder stop a machine?

Answer 2

No it can only help to slow down the vehicle or piece of equipment

Question 3

Where are three locations a hydraulic retarder can be located?

Answer 3

At the end put between the transmission and the torque converter.
At the output of the transmission.
And in a remote location or driveline

Question 4

What are some basic components of a hydraulic retarder?

Answer 4

Rotor, housing (stator), oil pump, oil cooler, control valve, wet brake and an accumulator

Question 5

What type of vanes can a rotor have?

Answer 5

Straight or angled

Question 6

What is the purpose of the retarder housing?

Answer 6

It encloses the retarder rotor providing a place for oil

Question 7

Where does the hydraulic retarder get its oil from?

Answer 7

The same oil circuit as the torque converter and transmission or another source

Question 8

At what temperature does oil burn off additives?

Answer 8

121 degrees Celsius or 250 degrees Fahrenheit

Question 9

What is another type of oil cooler other than oil to coolant type?

Answer 9

Oil to air cooler

Question 10

Retarder’s are controlled by three methods they are?

Answer 10

Manual operator control, air over hydraulic controls, electronic control

Question 11

What switches and sensors are involved in an automatic control valve and circuit?

Answer 11

Ignition switch, mode selection switch or lever, clutch position switch and transmission and gear indicator, a fuel control position indicator (throttle position sensor)

Question 12

If the ignition is off can the hydraulic retarder activate?

Answer 12

No it cannot

Question 13

True or false. Are all hydraulic retarders modulated?

Answer 13

Some are not modulated they are either on or off

Question 14

If a hydraulic retarder can be modulated by the operator. Is it done manually, pneumatically or either?

Answer 14

It can be modulated manually or pneumatically.

Question 15

When is a wet brake system activated?

Answer 15

While the hydraulic retarder is Filling with oil. It is released once the hydraulic retarder is operational.

Question 16

Why are hydraulic accumulator is used more on hwy or trucking applications?

Answer 16

Because in Offroad equipment we have a larger hydraulic pumps

Question 17

Does a air accumulator have springs?

Answer 17

No it does not

Question 18

How is an air accumulator triggered?

Answer 18

With a solenoid

Question 19

How much oil is left in the retarder housing when the retarder is not in use?

Answer 19

Just enough to lubricate moving parts.

Question 20

Can a hydraulic retarder be used in conjunction with an engine or exhaust brake?

Answer 20

Yes all three can be used at the same time

Question 21

Out of the three auxiliary braking systems, which is activated first?

Answer 21

The engine or exhaust break will be activated first. On long downhill grades the hydraulic retarder will be activated

Question 22

What is the energy conversion in a hydraulic retarder?

Answer 22

Kinetic energy by moving the vehicle is turned into heat energy from turbulence in the oil

Question 23

When does the rotor turn freely?

Answer 23

When the vehicle or piece of equipment is moving

Question 24

Is friction inside the hydraulic retarder higher or lower when oil is added?

Answer 24

The more oil added the more friction is created, slowing the output down

Question 25

What can happen if the retarder oil temperature rises higher than 135°C?

Answer 25

If the temperature rises above 135°C it can cause damage to the retarder. To avoid this you must apply the service brake or put the transmission in a lower speed

Question 26

What is required on a torque converter if the retarder is mounted in between the crankshaft flange and the flywheel?

Answer 26

The torque converter must have a lock up clutch

Question 27

How much torque is the torque converter multiplying when the retarder is activated?

Answer 27

The torque converter should not be multiplying torque

Question 28

When is the retarder most efficient?

Answer 28

When it is connected directly to the driveshaft

Question 29

When is a synchronizing valves used with a retarder?

Answer 29

When there is two transmissions on a piece of equipment. The synchronizing valve will prevent engagement of one transmission until the other transmission is in the right relation

Question 30

What happens when a hydraulic retarder is too small for its application?

Answer 30

It will create too much heat and deteriorate the oil quality.

Question 31

In what type of working condition should you increase oil change intervals?

Answer 31

When the equipment is working in mountainous terrain's and carrying heavy loads

Question 32

The powertrain ECM needs what inputs?

Answer 32

Throttle position sensor,retarder oil temperature sensor, output shaft speed sensor, retarder enabled device, break application pressure sensor

Question 33

Which outputs are controlled by the powertrain ECM?

Answer 33

Retarder control valve solenoid? Warning light, brake lights, over temperature light

Question 34

What tools can help you troubleshoot and diagnose hydraulic retarder electrical faults?

Answer 34

A scan tool, Digital multimeter, a fault code light system

Question 35

Why should you check the magnetic plug or filter elements?

Answer 35

If you find different metals on the magnet or in the filter it can help you troubleshoot the retarder

Question 36

What could be the problem if you find shiny steel particles on the magnetic plug?

Answer 36

Possibly a pump failure or the pump is wearing

Question 37

What could be a problem if you find aluminum particles inside the filter element?

Answer 37

It could be the retarder rotor wearing

Question 38

What could be a problem if you find rubber particles inside the filter element?

Answer 38

You could have a seal or hose failure

Question 39

If you find iron or steel chips on the magnetic plug or inside the filter elements what could be the problem?

Answer 39

There are broken components