Ironhydroxide
05-21-2014, 01:32 AM
OK, so I have spent some time reading through the transmission thread i wrote a while back. I believe that some of us need a bit simpler explanation of transmissions, more a basic "how stuff works" setup.
(credit: I took alot of these from Unabomber's manifesto from Nasioc)
So, here we go with some Links to some good reading.
Simple Transmission Walkthrough (http://www.howstuffworks.com/transmission.htm)
Clutch Walkthrough (http://auto.howstuffworks.com/clutch.htm)
Differential walkthrough (http://auto.howstuffworks.com/differential.htm)
http://www.youtube.com/watch?v=K4JhruinbWc
now you have the basics of how the transmission gets the power from the engine (clutch), how that power is transferred through the transmission (transmission), and how that transmission transfers power through the differential to the axles (differential).
so, what does a subaru transmission look like on the inside?
http://i757.photobucket.com/albums/xx213/ironhydroxide2/RiggedPerformance/IMG_20130325_224620_zpsf6989c78.jpg (http://s757.photobucket.com/user/ironhydroxide2/media/RiggedPerformance/IMG_20130325_224620_zpsf6989c78.jpg.html)
http://www.wallpaperinstaller.com/scooby/dogbox.jpg
1. Mainshaft
2. Mainshaft support bearing
3. 1st drive gear
4. Reverse drive gear
5. 2nd drive gear
6. 3rd drive gear
7. 3/4 selector hub
8. 4th drive gear
9. Mainshaft thrust bearing
10. Output shaft thrust bearing
11. 4th driven gear
12. Speedo drive
13. 3rd driven gear
14. 2nd driven gear
15. 1/2 selector hub
16. 1st driven gear
17. Pinion shaft support bearing
18. Pinion
19. Ring gear
20. Stub axle
21. Front LSD
22. 5th drive gear(not shown, behind #9)
23. 5th driven gear(not shown, behind #10)
So, now we know what everything is called, and roughly what things look like.
Remember in the first read through, how the selector hub engage the gear, locking it to the shaft?
well, there are different ways we can engage these. So. On to the next part.
What types of engagement are available? This is a common source of confusion when searching for information on transmissions. There are two types of engagement: Synchro and Dog.
Synchro engagement (also known as synchromesh) is what most passenger cars use.
Advantages:
a. Smooth operation on the road
b. No special driving style required
Disadvantages:
a. Synchros and shifting forks can break when abused and shifted aggressively
b. Slower to shift vs. dog engagement
Dog engagement is what most race prepared vehicles use.
Advantages:
a. Engage at any rpm
b. Allows for wider gear design
c. Will flat shift (Flat shifting is a practice where the clutch or gas do not need to be totally lifted in order to shift. Users will slightly lift one or the other to unload the dogs to allow a very fast shift)
Disadvantages:
a. Difficult to drive on the road
b. Recommended only for race use
c. Special care required under normal street use
What is a dog box? A dog box is the term for a transmission utilizing a dog engagement. A dog box can have either helical or spur gears or both.
What is a half dog box? A half dog box utilizes a combination of synchro and dog engagement. It depends on the manufacturer and customer preferences. Generally speaking, the first and second gears are dog engagement and the rest of the gears are synchro engagement. A half dog box can have either helical or spur gears or both.
What is synchronizer (synchro) engagement?
Synchros are synchronizers inside the transmission. These are the actual parts that move when you move your gear shift from side to side and back and forth. Their job is to connect the gears of the transmission to the shafts that they ride on and lock them together. This must be done at a gradual rate or the gears will grind. The synchronizer drives a cone shaped metal piece against the gear and starts the gear spinning. It accelerates it to the speed of the output shaft. When the gear reaches the speed of the output shaft, the synchro meshes completely with both of them and directs drive through its splines from the gear to the output shaft or vice versa.
What is dog engagement? Dogs are basically no more than cogs on a slider. The shifter pushes them into a receiver ring which engages the gear it is attached to. There is a separate dog and receiver for each gear in the transmission. On a racing transmission, there is a lot of "slop" (the gaps in the receiver are a lot larger than the teeth on the dog), which makes it easier to move into and out of the gears at higher RPMs without fully engaging the clutch.
Can a dog box be driven on the street? Though generally reserved for race applications, many users drive dog boxes on their daily driven vehicles. To do so, you need to learn proper shifting techniques and rev matching skills to decrease wear on the dog gears. The Shifting FAQ, this article, local personnel, or your transmission professional should be able to provide assistance with proper shifting techniques. This is one decision that should not be made lightly. If there is the slightest doubt in your mind as to your technique or attitude towards a daily driven dog box, you should opt for a synchro engagement transmission. Another thing to keep in mind is that a dog box is definitely not an option for a vehicle that sees occasional use by others such as your spouse, friends, visitors, valet, etc.
What is the biggest transmission misconception? That when you shift gears, you are physically engaging the teeth of the transmission. As seen in the picture above, the teeth of your transmission are always engaged, meshed, and moving. When you shift gears, what you are doing for both dog and synchro engagement is engaging the sliding mechanism inside the gears to apply power to the selected gear. When this occurs, a load is generated in that gear and forward motion occurs.
What is the second biggest transmission misconception? Case flex occurs within Subaru transmissions. Here is how the Subaru 5MT transmission case appears removed from the vehicle:
http://www.wallpaperinstaller.com/scooby/top.jpg
http://www.wallpaperinstaller.com/scooby/side.jpg
The front transmission section houses the gears and is opened by removing the left and right half shells to expose the gears. These shells are bolted to each other as well as held in place by being bolted to the engine block and the rear transmission section which is another solid piece. Looking at the construction, it is impossible for the housing to flex.
Even if flex occurred, the gears sit on top of each other, so if flexing to any degree occurred, the gears would actually come together firmer due to gravity than apart as some contend. The premise of case flex when looked at from a construction aspect is a moot point and aside from the evidence listed here, there are any number of other reasons in the internal construction that any transmission professional can go over in further detail.
NOW that you've read this, and know a bit more... ON to the real specified information
http://thefactoryfiveforum.com/showthread.php?9909-THE-Transmission-Thread-2-0-Now-with-Pictures
(credit: I took alot of these from Unabomber's manifesto from Nasioc)
So, here we go with some Links to some good reading.
Simple Transmission Walkthrough (http://www.howstuffworks.com/transmission.htm)
Clutch Walkthrough (http://auto.howstuffworks.com/clutch.htm)
Differential walkthrough (http://auto.howstuffworks.com/differential.htm)
http://www.youtube.com/watch?v=K4JhruinbWc
now you have the basics of how the transmission gets the power from the engine (clutch), how that power is transferred through the transmission (transmission), and how that transmission transfers power through the differential to the axles (differential).
so, what does a subaru transmission look like on the inside?
http://i757.photobucket.com/albums/xx213/ironhydroxide2/RiggedPerformance/IMG_20130325_224620_zpsf6989c78.jpg (http://s757.photobucket.com/user/ironhydroxide2/media/RiggedPerformance/IMG_20130325_224620_zpsf6989c78.jpg.html)
http://www.wallpaperinstaller.com/scooby/dogbox.jpg
1. Mainshaft
2. Mainshaft support bearing
3. 1st drive gear
4. Reverse drive gear
5. 2nd drive gear
6. 3rd drive gear
7. 3/4 selector hub
8. 4th drive gear
9. Mainshaft thrust bearing
10. Output shaft thrust bearing
11. 4th driven gear
12. Speedo drive
13. 3rd driven gear
14. 2nd driven gear
15. 1/2 selector hub
16. 1st driven gear
17. Pinion shaft support bearing
18. Pinion
19. Ring gear
20. Stub axle
21. Front LSD
22. 5th drive gear(not shown, behind #9)
23. 5th driven gear(not shown, behind #10)
So, now we know what everything is called, and roughly what things look like.
Remember in the first read through, how the selector hub engage the gear, locking it to the shaft?
well, there are different ways we can engage these. So. On to the next part.
What types of engagement are available? This is a common source of confusion when searching for information on transmissions. There are two types of engagement: Synchro and Dog.
Synchro engagement (also known as synchromesh) is what most passenger cars use.
Advantages:
a. Smooth operation on the road
b. No special driving style required
Disadvantages:
a. Synchros and shifting forks can break when abused and shifted aggressively
b. Slower to shift vs. dog engagement
Dog engagement is what most race prepared vehicles use.
Advantages:
a. Engage at any rpm
b. Allows for wider gear design
c. Will flat shift (Flat shifting is a practice where the clutch or gas do not need to be totally lifted in order to shift. Users will slightly lift one or the other to unload the dogs to allow a very fast shift)
Disadvantages:
a. Difficult to drive on the road
b. Recommended only for race use
c. Special care required under normal street use
What is a dog box? A dog box is the term for a transmission utilizing a dog engagement. A dog box can have either helical or spur gears or both.
What is a half dog box? A half dog box utilizes a combination of synchro and dog engagement. It depends on the manufacturer and customer preferences. Generally speaking, the first and second gears are dog engagement and the rest of the gears are synchro engagement. A half dog box can have either helical or spur gears or both.
What is synchronizer (synchro) engagement?
Synchros are synchronizers inside the transmission. These are the actual parts that move when you move your gear shift from side to side and back and forth. Their job is to connect the gears of the transmission to the shafts that they ride on and lock them together. This must be done at a gradual rate or the gears will grind. The synchronizer drives a cone shaped metal piece against the gear and starts the gear spinning. It accelerates it to the speed of the output shaft. When the gear reaches the speed of the output shaft, the synchro meshes completely with both of them and directs drive through its splines from the gear to the output shaft or vice versa.
What is dog engagement? Dogs are basically no more than cogs on a slider. The shifter pushes them into a receiver ring which engages the gear it is attached to. There is a separate dog and receiver for each gear in the transmission. On a racing transmission, there is a lot of "slop" (the gaps in the receiver are a lot larger than the teeth on the dog), which makes it easier to move into and out of the gears at higher RPMs without fully engaging the clutch.
Can a dog box be driven on the street? Though generally reserved for race applications, many users drive dog boxes on their daily driven vehicles. To do so, you need to learn proper shifting techniques and rev matching skills to decrease wear on the dog gears. The Shifting FAQ, this article, local personnel, or your transmission professional should be able to provide assistance with proper shifting techniques. This is one decision that should not be made lightly. If there is the slightest doubt in your mind as to your technique or attitude towards a daily driven dog box, you should opt for a synchro engagement transmission. Another thing to keep in mind is that a dog box is definitely not an option for a vehicle that sees occasional use by others such as your spouse, friends, visitors, valet, etc.
What is the biggest transmission misconception? That when you shift gears, you are physically engaging the teeth of the transmission. As seen in the picture above, the teeth of your transmission are always engaged, meshed, and moving. When you shift gears, what you are doing for both dog and synchro engagement is engaging the sliding mechanism inside the gears to apply power to the selected gear. When this occurs, a load is generated in that gear and forward motion occurs.
What is the second biggest transmission misconception? Case flex occurs within Subaru transmissions. Here is how the Subaru 5MT transmission case appears removed from the vehicle:
http://www.wallpaperinstaller.com/scooby/top.jpg
http://www.wallpaperinstaller.com/scooby/side.jpg
The front transmission section houses the gears and is opened by removing the left and right half shells to expose the gears. These shells are bolted to each other as well as held in place by being bolted to the engine block and the rear transmission section which is another solid piece. Looking at the construction, it is impossible for the housing to flex.
Even if flex occurred, the gears sit on top of each other, so if flexing to any degree occurred, the gears would actually come together firmer due to gravity than apart as some contend. The premise of case flex when looked at from a construction aspect is a moot point and aside from the evidence listed here, there are any number of other reasons in the internal construction that any transmission professional can go over in further detail.
NOW that you've read this, and know a bit more... ON to the real specified information
http://thefactoryfiveforum.com/showthread.php?9909-THE-Transmission-Thread-2-0-Now-with-Pictures