190303c powershift components

Question 1

A machine comes in, it has an external reservoir, the customer complaint is that the overheating warning for transmission light comes on when driving and the oil level is high when you check it, the oil doesn’t look contaminated, what is the most likely cause of this issue : operator claims he hasn’t put any new oil in it? pick the best answer and explain it:
A. overfilled transmission by customer
B. oil cooler (oil to coolant type) failure
C. scavenge pump failure
D. cracked hydraulic tank
C. hydraulic pump failure

Answer 1

C. Hydraulic pump failure, as the pump seal will usually be facing internally on the torque converter housing, it would allow the same type of oil to leak (or similar oil) into the converter, and the scavenge pump will pull oil into the transmission (as it supplies the lubrication and torque converter circuit, the pump is running separate hydraulics) from the torque converter housing causing a higher oil level in the transmission

Question 2

What is the function of a transmission?

Answer 2

To provide speed changes, a reverse, a neutral, and a pto

Question 3

What are the two types of transmissions and explain which each one is designed for

Answer 3

Automatic transmissions for hauling applications and powershift transmissions for cycling applications

Question 4

What is the benefit of a powershift or automatic transmission?

Answer 4

allows operator to shift while under power or under load

Question 5

Which transmission allows operator to control speed or shifting?

Answer 5

powershift transmission

Question 6

What absorbs end thrust on planetary gear sets?

Answer 6

brass or steel thrust washers between the gear ends and the carrier

Question 7

What are some benefits to planetary transmissions?

Answer 7

Smaller transmissions compared to countershaft transmissions, gears are always in constant mesh, many different combinations of speeds and directions can be used, versatility

Question 8

how many different speed and direction combinations IN TOTAL can a planetary provide?

Answer 8

5 different, but in total 8 in theory

Question 9

What are the conditions of every gear in a planetary gear when it is in first speed reduction

Answer 9

Sun gear input, carrier output, internal held

Question 10

What are the conditions of every gear in a planetary gear when it is in second speed reduction

Answer 10

internal input, carrier output, sun held

Question 11

What are the conditions of every gear in a planetary gear when it is first speed overdrive

Answer 11

carrier input, internal output, sun held

Question 12

What are the conditions of every gear in a planetary gear when it is second overdrive

Answer 12

carrier input, sun output, internal held

Question 13

What are the conditions of every gear in a planetary gear when it is reverse 1st speed

Answer 13

carrier held, sun input, internal output

Question 14

What are the conditions of every gear in a planetary gear when it is reverse 2nd speed

Answer 14

carrier held, internal input, sun output

Question 15

What are the conditions of every gear in a planetary gear when it is a neutral condition

Answer 15

when the is an output but no held members, no input to the gear set

Question 16

What are the conditions of every gear in a planetary gear when it is direct drive

Answer 16

locking two members together, or driving two members of a gear set at the same speed (rpm), in the same direction

Question 17

describe the inputs and outputs of the three different types of planetaries in terms of input output configurations

Answer 17

multiple planetary transmission: in on the sun, out on the internal gear, double input, in on the sun out on the carrier, double output: in on the sun out on the sun

Question 18

What is tooth speed?

Answer 18

The number of gear teeth passing by a given point in a given period of time and is measured in teeth per second

Question 19

what would a positive tooth speed forward, and negative tooth speed be as a condition in a planetary if the tooth speed were both of the same number?

Answer 19

neutral condition

Question 20

would would a higher tooth speed on the internal gear compared to the input gear (sun gear): for example tooth speed of the sun gear is 4 tps, and internal is 8 tps

Answer 20

it would be considered a reduction

Question 21

what would an equal rpm of the sun and internal gear if the tooth speed of the sun was lower, and the tooth speed of the internal was way higher and why

Answer 21

a direct drive, as they both are driving at equal rpm

Question 22

internal gear rotating in reverse at a much higher tooth speed than the sun gear is rotating forward, what condition would the planetary be in?

Answer 22

reverse

Question 23

What are the lands used for on clutch friction discs?

Answer 23

holding oil to the discs when not engaged, and squeezing the oil out when engaged

Question 24

What is the purpose of a hole with a ball in a clutch piston?

Answer 24

a sort of dump valve, or orifice, could be also for modulation

Question 25

what are holes in the sides of a rotating clutch housing for? and why?

Answer 25

release of oil for when the clutches are throwing oil off of them due to centrifugal force, other wise oil could build up inside the housing and create issues

Question 26

what gearing configuration has all the gears moving at the same time?

Answer 26

countershaft gearing configurations

Question 27

what type of clutches are normally in a transmission?

Answer 27

hydraulic applied, spring released of the rotating type

Question 28

What types of clutches are there (there are 2)

Answer 28

fixed and rotating

Question 29

Why are countershaft transmissions bigger?

Answer 29

thrust loads are not as balanced as in planetary types