Constant Velocity (CV) joints are used to apply power from the final drive to the wheels. Without these we wouldn't be able to allow for the vertical and lateral movement of the wheels. Cv's are comprised of two races (inner and outer) that are connected via ball bearing held in a cage. They are quite long lasting if correctly lubricated.
Clutches transfer the power from the flywheel (Engine) to the input shaft (Gearbox) in a manual setup. The two main parts in a clutch are the pressure plate and the clutch plate. A thrust bearing applies load from the slave cylinder onto the pressure plate. When the bearing is not engaged with the pressure plate, the pressure plat eis clamping the clutch plate (Friction plate) onto the flywheel. When you push the clutch in the pressure is released from the clutch plate and allowed to spin freely from the flywheel. It is very important to align clutches properly and to machine the flywheel when installing clutches. If the flywheel isnt flat the clutch will have unbalanced wear and will wear much quicker. When you bolt up the clutch to the flywheel ensure the plate is aligned to the flywheel (spiget bearing). This ensure the gearbox will slide in much easier.
Drive Shafts transfer the drive from the rear of the gearbox to the differential in a RWD setup. The are generally made of one or two shafts that are connected by Universal Joints. They are generally pretty full proof unless you have a imbalance or worn out UJ. To rectify a imbalance take a runout test of the shaft at the front middle and rear. Add a hose clip to the shaft to counteract the imbalance of the shaft. It may take a number of attempts to get it spot on.
Thursday, June 16, 2011
4844 Transmission and Drivelines - Manual Fwd Gearbox Disassemble and Re-assemble
The FWD Gearbox transfers the torque and power of the engine to the wheels. It has a number of gears that mesh in order to provide higher and lower gear ratios. Higher gear ratios mean car can take off and drive up steep gradients. The lower ratios mean higher speeds are available at lower RPM to achieve better efficiency.
The Disassembling Was relatively easy, Although The gearboxes we used had not been apart many times so the 5th gear was relatively tight on the shaft. We didnt have the correct service tool to remove the gear but as a last measure used a puller that acted on the gear itself. This was done very carefully to ensure no damage to teeth occurred.
When inspecting the gears i looked for any pitting, chips or grooves. All the gears were in surprisingly good condition. Although as expected the reverse sliding gears had a little more wear than the rest but it would have been fine to return into service.
During the time the gearbox was apart i learned about the detent mechanisms and the interlock mechanisms. The detent balls and springs hold the gear shafts in place so the gearbox wont slip out of gear. The interlock stops the driver from selecting 2 gears at the same time. It is a very important part and is highly efficient yet is only comprised of two ball bearings.
Reassembling took longer than planned. The shafts are a bit tricky to put in correctly however with a bit of unplanned practice i soon got quicker. Due to me forgetting to turn the reverse gear idler shaft to the correct point to ensure it lines up with the casing. A Mistake i will not make again is it was very time consuming.
Once reassembled the gearbox went through all the gears properly and didnt have any issues. Great success.
The Disassembling Was relatively easy, Although The gearboxes we used had not been apart many times so the 5th gear was relatively tight on the shaft. We didnt have the correct service tool to remove the gear but as a last measure used a puller that acted on the gear itself. This was done very carefully to ensure no damage to teeth occurred.
When inspecting the gears i looked for any pitting, chips or grooves. All the gears were in surprisingly good condition. Although as expected the reverse sliding gears had a little more wear than the rest but it would have been fine to return into service.
During the time the gearbox was apart i learned about the detent mechanisms and the interlock mechanisms. The detent balls and springs hold the gear shafts in place so the gearbox wont slip out of gear. The interlock stops the driver from selecting 2 gears at the same time. It is a very important part and is highly efficient yet is only comprised of two ball bearings.
Reassembling took longer than planned. The shafts are a bit tricky to put in correctly however with a bit of unplanned practice i soon got quicker. Due to me forgetting to turn the reverse gear idler shaft to the correct point to ensure it lines up with the casing. A Mistake i will not make again is it was very time consuming.
Once reassembled the gearbox went through all the gears properly and didnt have any issues. Great success.
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