Drive Shafts And Universal joints- C.V Joints and Clutches (week three) and Final Drive-Differential (week four)

Today we got to work on CV Joint. We first did a visual inspection, i found that cv boot was ripped and that the cv housing had cracks and the splines were teared. This caused the cv joint not meshing in properly with the shaft. As i started to take it apart i found that the circlips were bent and that it would not lock in properly and hold the tripod in place when re-assembling it. I took the balls out and re-greased them before putting it back in its housing. Both joints was moving and working smoothly. We found rust on the tripot shaft ends, dents and scratching were visible on the exterior body. The balls were not discolored and looked in good condition. We started doing clutches the next  day and were checking how to adjust Pedal free play and how it is caused. Most of the time just the clutch cables needed to be tightened from behind the pedal or maybe at the fire wall by way of tighting the nut. The clutch plate we were looking at was burned and worn out due to riding the clutch. We then started to check the run out of the flywheel and found it to be 0.14. Its also important to know what side the clutch plate goes on when re-assembling it, this is known by looking at the clutch plate and fitting the flat side of the clutch against the flywheel. We then checked the universal joint shaft for play. There was little play and could be fixed by replacing it and also i recommend balancing the drive shaft and replacing the snap ring.

Driveshaft:
Drive shafts, in general, are mechanical components that pass on torque and rotation with the aim of connecting other part of the drive train.Transmits power from the transmission to the final drive.  Universal joints at each end allow for an angular change in driveline.  Universal joint is commonly a cross joint which consists of 4 roller bearings and a cross which joins 2 yokes together. Normall serving on drive shaft would include adding weight on and re-balancing balance the shaft which will reduce vibration.


CV joints (constant velocity):
Used in FWD and 4WD vehicles to transmit power from the transmission to the wheels or final drive.  In a front wheel drive vehicle there are CV joint's located at the output from the transmission and at the wheel hub.  The inner joint is often of different design as it allows for the in and out movement of the suspension, can be a tripod joint which consists of 3 rollers inside sleeves.  The outer joint allows for easy circular movement but not in and out movement, consists of ball bearings inside a ball cage surrounding the inner race that is splined in the middle for connection to shaft.
Clutch disk, pressure plate, release bearing/fork, clutch housing.
a clutch allows the engine to be disconnected from transmission. When clutch pedal is pushed in a cable or hydraulics are used to press the release bearing into the fins of the pressure plate.  As fins are pushed in the clutch is pulled off the flywheel allowing the transmission to change into a different gear ratio.

Differential consists of a crown wheel, pinion, spider gears, side gears, adjustable side bearings, spacer. The differentialr-final drive transfers power from the driveshaft to the rear axle and wheels.  Pinion gear meshes with the crown wheel which turns the spider/side gear case thats splined to rear axle.  When the car is traveling  in a straight line the spider gears and side gears turn with the case but if the vehicle is turning a corner one wheel turns faster than the other. Gears which are worn will not mesh properly and the differential will not operate and also will reduce the life span of the components.

Manual Transmissions (week two)

In transmission this week we  took apart a  manual transmission. We first started by doing a pre-dismantle check to make sure there wasn’t any souvier cracks or damage and wear and tear. I did not see any of these signs and there was nothing missing. We first started by taking of the shell of the gearbox and then removed the external components and got to taking the gears of and the shift forks and levers. We did a visual inspection the gears and we did not find cracks on teeth or warping or bending of gears and they meshing properly with the other gears. We started to do the checks on the books such side clearance with the use of some feeler gauges and checking the baulk rings and so on. Then we started to calculate the gear ratios of the gears by marking one teeth with marker and counting the number of teethes on each gear and then dividing the driven gear to the driver gear. We completed the tasks on the sheet then started to assemble back the gears and the rest of the components.
A manual gear box transmission allows the driver to manually select gears for use in its optimum RPM range. transaxle gearbox incorporates the differential which is in use on fwd cars such as Subaru. The gear stick operates the selector mechanism which incorporates the selector forks and shafts. The detent mechanism holds shafts in place and aligns them properly. The interlock mechanism is different and will stop the selectors from locking into different gears while one is selected than. The driving gears on the input shaft will drive the free spinning gears or so called the driven gears on the shaft that includes the pinion gear. The driven spinning gears movement is slowed down by the baulk rings before the selector forks will lock them into place. When a gear will be selected it will transfer the drive to the pinion gear and out to the crown. From there the movement is tranferred to the wheels.

Automatic Transmissions (week one)

  For the first week of transmissions we got to strip down a automatic transmission have a look at it and inspect it and then put it back together. We learnt the functions of most of the components in a transmission in practical and theory and how an automatic trans operates.

An automatic gear box is atype of veichle trans which can automatically change the gear ratios as the vehicle moves, this makes it easy for the driver to shift gears as he does not have to do it manually. To select the transmission operating mode, the driver moves a selection lever located either on the steering column or on the floor.

Funtion of the main parts in automatic trans:

Oil pump: The oil pump gives pressurized oil for the control systems in the transmission and also for cooling of the components and lubrication.

Torque converter:

 

Cars with an automatic transmission have no clutch that disconnects the transmission from the engine. Instead they use a torque converter. A torque converter is a type of fluid coupling, which allows the engine to spin independently of the transmission. 

There are four components inside the very strong housing of the torque converter:

•  Pump: The pump inside a torque converter is a type of centrifugal pump. As it spins, fluid is flung to the outside

•  Turbine is the driven member
•  Impeller is the driving member 
• Stator reverses the direction of the fluid. A one-way clutch (inside the stator) connects the stator to a fixed shaft in the transmission

The engine drives the impeller in the torque converter which in turn forces oil out in to the turbine. The tourqe will be moved down to the input shaft. There is a stator between the impeller and the turbine which redirects. The stator is there to redirect the oil flow as it enters the impeller and is also there to increase torque. This is so that the oil enters the impeller in the same direction as the impeller is turning

valve body controls the transmission the brain of automatic transmission. it connects to the oil pump, servo, clucth ,torque converter.There are two general types of valves, valves act on the shift valves at opposing ends of the valve to control the point at which

the transmission will shift gear.