summary courses
- 2401 (3.5 weeks)
- drive axle #3
- clutches (on-road) #1
- driveline #2
- 2425
- business
- all semester
- 3 hrs per week
- need book!
- clutches
- engaged: foot off pedal (not depressed), driving
- disengaged: foot on pedal (depressed), not moving
- operation
- push type: light / medium duty
- bearing only spin when it is pushed towards the clutch
- driving on the road, bearing not spin
- pull type:
- clutch brake is available which helps to stop trans, so we can shift forward or reverse, located bw relief bearing and seal housing
- step on clutch all the way while moving, all load are imposed on clutch brake
- use cutting torch to remove clutch brake once it failed
- 1 piece brake is worse than 2 piece
- spring type & diaphram type (automotive)
- no way to adjust the clutch if clutch is wear
- spring force
- 120 lbs x 6 springs x 3 (level ratio)
- threads on friction dics
- help release the clutch
- path for wear metal go out
- torsional spring on clutch disc help absorb torsional load from engine
- clutch dics material: bimetalic ceramic, fiber.
- diesel engine:
- don’t need to apply throttle when slowly release the clutch because government take care of the rpm
- gasoline:
- release clutch while apply throttle, or engine stop
- free pedal: operator press on pedal a little bit before feel the resistance
- clutch cover light duty stamped steel (light), heavy duty cast iron
- self-adjusted clutch & non self-adjusted clutch
- start dismantle clutch from bottom bolts
- torsional shock load hammers clutch teeth, synchronizer
- slippage:
- improper adjustment due to wear, thus losing application force
- oil get into the clutch assembly
- broken springs
- worn out
- foot on pedal
- start in too high gear
- path of power: fw, clutch cover, pressure plate, clutch discs, trans input shaft
highway clutches
- functions
- connect drive and driven unit
- provide smoothly transmitting power during engagement
- temporarily disengaging an engine help the shifting process or stop
- terms: release levers, release bearing, lining, clutch discs, pressure plate, clutch cover, pressure spring
- types
- push-type (light to medium duty)
- clutch release shaft and yoke assembly push a release bearing toward the clutch release levers
- pull type (medium to heavy duty)
- mechanical linkage pulls a release bearing and sleeve assembly away from flywheel
- clutch actuation methods
- mechanical
- used when cab & trans are located near together
- more wear and lub points
- susceptible to contamination
- cheap
- hydraulic
- similar hyd brake
- flexible for distance (used in buses)
- if lines breaks or master cyl fail, the clutch will not release
- air
- air-over-hyd to help boost pedal force
- clutch is engaged by venting the air pressure
- components
- size of clutches determined by
- dia of the clutch disc
- outside dia of the clutch shaft
-
splines in the hub
-
of dampening springs
- flywheel
- has pilot bearing in the bore to pilot the trans input shaft
- flat flywheel
- the clutch cover plate is fastened to the outside of flywheel
- work with single or double discs
- countersunk
- can work with double discs
- have intermediate plate driven by flywheel
- clutch cover (drive unit)
- contain pressure springs
- contain and drive pressure plate
- always rotate with flywheel
- cast iron (heavy duty), stamped steel (light duty)
- pressure spring (drive unit)
- perpendicular coil
- angled coil
- diaphragm spring
- clutch discs
- rigid clutch discs
- used in a limit amount of engagement and disengagement applications
- dampened clutch discs
- has torsional spring to absorb shock loads
- linings
- has some slippage and heat during engagement before it’s firmly clamped
- organic (NAO or non asbestos organic linings)
- ceramic (heavy duty)
- intermediate plate
- used in double disc clutch
- driven by flywheel through drive pins
- can be driven by clutch cover
- must move slight during engagement and disengagement in flywheel or clutch cover to prevent clutch discs remain in contact with friction surface
- anti-rattle springs help to restrict intermediate plate (IP) vibration and reduce noise, located bw IP and drive pin
- release levers
- move pressure plate closer to clutch cover by compress the springs
- release bearing
- used to move release levers
- push type: bearings only rotate during en/dis-engagement process
- pull type: bearing rotate all the time, but rotate under load during en/dis-engagement process
- can has clutch brake assembly
- path of power
- drive: flywheel, clutch cover, pressure plate intermediate plate
- driven: clutch discs, transmission input shaft
- adjustment
- wear components: flywheel, pressure plate, intermediate plate, linings
- manual
- push type: adjust @ a threaded rod that moves the release bearing yoke shaft
- pull type: adjust @ an internal ring (must unlocked)
- self-adjustment
- self-adjuster work @ dis/engagement process
- there’s a adjusting limit to prevent clutch’s adjusted to tightly causing premature wear of release bearings and release levers
- clutch brake
- stop rotation of clutch discs and trans input shaft on shifting from neutral to first or reverse gear
- applied when the clutch pedal is pushed to the floor
- multiple disc clutch brake
- torque-limiting (one piece) clutch brake
- slip @ a certain torque load
- service
- keep internal area of the clutch housing cleaned
- adjust and lub release bearing
- prevent clutch-to-the-floor on shifting
- slipping
- slippage cause heat, should prevent slippage
- change engine oil seal leaks
- trying move @ high gear can cause slippage
- dragging
driveline
universal joint
- variable velocity joint
- carend joint
- non-uniform motion
- put 2 u-joint inline (refer as facing)
- different is canceled with 2 u-joint
- brinelling
- true
- false
- prevent brinelling by mounting side to side, so crossshaft is not perpendicular to the ground
- the angle depends on rpm
- no angle damage bearing surfaces
- function
- transfer power (truck transmission to drive axle)
- drive other things
- application
- engine to trans
- trans to aux trans
- aux trans to transfer case
- transfer case to front drive/rear axle/pto
- shaft 60” max, more than that, broken more shafts
driveline
- use jack on u-joint and pound it to remove a seized u-joint
- no grease, (incorrect lub)
- pitting (can caused by dirt, water), scoring
- brinelling
- check angle: always compare font end to the rear end
- higher @ front lower @ the rear
- use positive # (blue #)
- measure angle on flat spot on engine cover
- lower @ front higher @ the rear
- driveline styles
- parallel design (ideal)
- intersecting driveline or broken bar
- components are rotate (components are located near together)
- oil level will be different, may starve the gears
- can increase oil level, but will increase heat!!
- intersecting 2 driveline
- facing
- put inclinometer (angle finder) on the york of 2 ends, should be same
- this check also helps to determine twisted shaft
- how much effect drive height effects my working angle?
- thus, we need to check height with air up and down
- driveline vibration cause damage synchro
- input driveline info to computer to figure out vibration
- tools: road ranger driveline analyzers
- can change axle housing to address viration
- use wedge to change the angle
- adjust the mid-ship with shims
- adjust the adjustable rod connecting axle housing with the frame by add shims
- there’s collerration bw the angle and rpm
- 2 types of angle checking methods
- side view
- plan view (top view)
- check for offset (can’t change this angle)
- spring suspension has to be loaded in order to give the correct angles
- usually it has no load, it will be out of alignment
- APC: apprentice provincial committees
- LAC: local apprentice committees
- NOP: national
- 1st red seal 1,2,3rd have conditioners
- 2nd red seal 1,2, 4th have automatic trans
misc
- variable velocity joint
- mark a slip joint to before disassembly to ensure the drive shaft is balanced when resembly
- an important step when replacing a u-joint is clean the drive shaft yoke bores.
- driveline cal
- trans: 2, 2
- green axle 4.1, 3.5
- red axle 7.8, 5.2
- axle housing 4.0, 7.3
- pressure plate assembly:
- pressure plate
- springs
- release levers
- clutch cover
- release bearing move forward when the linning wear
- lose free pedal (release yoke and release bearing) when clutch wear
- a loud growling noise (fully diseange), defective release bearing and sleeve
- double disc clutch, position discs so their hubs don’t contact each other
- no free pedal causes clutch slip
- pivot point for the release yoke and shaft assembly located in the clutch housing
- defective pilot bearing make noise when the pedal is pushed to the floor and held
- excessive clutch free pedal, hard shifting or grinding on shifting because is not fully disconnected
- first step to readjust worn clutch
- check and adjust release bearing to clutch brake clearance by adjusting the ring
drive axle
- functions
- withstand and support the vehicle’s weight and load
- provide last gear reduction
- change path of power by 90
- allow the wheel speed differences
- path of power
- input yoke
- input pinion
- ring/bevel/crown gear
- differential case (flange half and plain half)
- differential cross shaft
- differential pinions (spyder)
- axle side gears
- axle shafts
- speed and torque in differential and wheels
- ring gear speed is equal to the sum of both axle torques
- assembly
- adjust pinion bearing preload
- adjust pattern
- adjust backlash
- service
- steam cleaning and soapy water may cause corrosion
- used petroleum-based cleaning solutions
- diff types
- single speed single reduction
- single speed double reduction: mack trans
- first reduction: input pinion and bevel gear
- second reduction: helical spur and bull gear
- two speed, planetary
- two reduction in low speed
- pinion input
- bevel gear output (1st reduction)
- planetary ring gear (planetary input)
- sun held to adjusting ring
- pc is output connected to diff case
- mild reduction!
- one reduction in high speed
- two speed, double reduction
- interaxle
- outboard planetary (in: sun, out: p.)
- IMPORTANT: lock the diff before removing the axle
- check 4 places on bevel gear for backlash before disassemble
- if those readings are varied a lot, we may need check run out
- it is better to put bearing caps on after seating the bearing cup with bearing adjusters.
- moisture in compressed air can damage bearing, but it provides fast drying process used in real life (not in module, because moisture cause corrosion, they said let it air dry - very long)
- spinning bearing while applying press load to seat the bearing
- spinning the bevel gear while doing side bearing preload
- tight on flange case until no backlash while spining ring gear
- back off 2 notches
- tight on plain case adjuster until outer race (cup) start to turn while spinning the ring gear
- torsen diff (toyota)
- gear only
- intanteneous lock
- inter axle service steps
- pinion preload
- nominal shim for nominal distance
- side bearing preload (don’t want it move, or contact pattern mess up)
- backlash (ring and pinion) heel and toe
- contact pattern
- end play of other junk!
- too much end play, driveline vibration
- dcdl: inter wheel, driver control diff lock
- engaged while spinning at diff speed bw sliding clutch and axle splines cause twisted
- diff lock on, no differential feature, hard to shift
- if we lose traction on the rear, font rear axle don’t spin thus ring gear don’t plash any oil.
- input shaft hold the oil gear shaft
- output shaft contains oil body spin, pump the oil support its axle
- stripped splines on a power divider input shaft (either splines of 3 splines ) : no drive to either axle assembly
- remove the drive shaft to the front drive axle assembly before removing a power diver differential assembly
- pinion bearing preload (norminal shim), pinion depth, carrier bearing preload, backlash