190303E

Question 1

function of a hydraulic retarder?

Answer 1

prevent engine from overspeeding and reduce use of service brakes

Question 2

what kind of braking system is a hyd retarder?

Answer 2

a supplementary or auxiliary braking system

Question 3

is a retarder meant to stop a vehicle?

Answer 3

no

Question 4

where are input, output, and remote mounted retarders located?

Answer 4

input: on input to transmission after torque converter
output: on output of transmission
remote: located on driveline

Question 5

the retarder used within a transmission is sometimes referred to as a?

Answer 5

input retarder

Question 6

if a retarder is between the engine and converter, what do you need to have on the converter?

Answer 6

a lockup clutch

Question 7

what is the most effective position for a retarder?

Answer 7

on the input, it enhances effectiveness when operator downshifts when retarder is being used

Question 8

how does the output retarder exert braking force?

Answer 8

exerts force directly on driveline, doesn’t care about engine rpm or tranny gear selection

Question 9

what is used to minimize the delay of oil to retarder housing when the retarder is activated?

Answer 9

multi-disc clutch packs can activate for a short period to begin the retarding process

Question 10

how does a remote retarder exert braking force?

Answer 10

same as output retarder

Question 11

what are the components of a hyd retarder?

Answer 11

retarder rotor
retarder housing
oil pump and supply circuit
oil cooler
retarder control valve and control circuit
wet brake system
accumulator

Question 12

where is the retarder rotor attached to?

Answer 12

torque converter output shaft, tranny output shaft or driveline

Question 13

where is the retarder rotor located?

Answer 13

in the retarder housing and sandwiched by stator/retarder housing

Question 14

what is the retarder/stator housing?

Answer 14

a stationary component, called a stator. encircles and encloses the retarder rotor

Question 15

where does the retarder get oil from?

Answer 15

the same oil pump that supplies oil to the torque converter/tranny if input mounted. if output mounted/remote, can have their own oil pump

Question 16

how is oil supplied to the retarder?

Answer 16

from the converter/tranny system then cooled by converter oil cooler

Question 17

on large haul trucks, what is used to cool the retarder oil?

Answer 17

an oil-to-coolant type of oil cooler, or oil to air

Question 18

there are 3 methods to control a retarder, what are they?

Answer 18

manual operator control
air over hydraulic control
electronic control

Question 19

purpose of a hyd retarder control valve assembly?

Answer 19

direct oil supply to retarder rotor housing

Question 20

what basic switches are used on automatic control valve and control circuits for the retarder actuation?

Answer 20

an ignition switch
a mode selection switch/lever
a clutch position switch+ tranny gear indicator
fuel control position indicator

Question 21

what actuation method is used for operator modulation of the reorder?

Answer 21

hydraulic or air activated

Question 22

what is a benefit of modulating the retarder?

Answer 22

limits heat created
extends service life of components, maintains oil quality

Question 23

Why would a wet brake system be used?

Answer 23

to limit lag time, faster apply retarder.

Question 24

why do retarders use an accumulator?

Answer 24

as a method of fast fill. mostly in trucking/highway

Question 25

when braking is not required, is the retarder housing full of oil?

Answer 25

no, only has lube oil

Question 26

what energy conversion does a retarder create?

Answer 26

kinetic to heat

Question 27

how does a retarder operate?

Answer 27

due to the friction between the moving rotor and oil

Question 28

how is oil slowed in a retarder?

Answer 28

by the shearing action of the oil between the rotor and oil

Question 29

is oil constantly running through the retarder control valve?

Answer 29

yes, but not always going to retarder

Question 30

if a hyd retarder is too small for the application, what will occur?

Answer 30

excessive hear and oil deterioration

Question 31

machines that operate in mountainous terrain need to be aware of what regarding service intervals?

Answer 31

may require a shorter oil change interval