In reading some of the threads posted about manual transmission, I see there are misconceptions on how they work. There are basically two different types of transmission-synchronized and unsynchronized or what is called a crash box.
Currently there are synchronized transmissions-is what is in your car and available on big trucks up to 6 speeds and 860lb/ft of torque. They shift by pushing in the clutch, moving the gearshift to the next gear without gear crunching-using cone clutches that synchronize the gear speed before allowing the shift to be completed.
When you get above 860lb/ft of torque, you get into double counter shaft transmission (use two opposing counter shafts to counter act any torque bending of the main shaft) 7 speed (no splitters); 9, 10 speeds with a high/low range selector; 13, 18 speeds with a high/low range selector and a gear knob mounted direct/overdrive splitter; 15 speed with a high/low range selector and a dash mounted creeper range selector; 10 and 11 speed double lows that have a high/low range selector and a shifting knob mounted creeper gear selector. All the transmissions above 7 speed (in the U.S.A.) are non synchronized transmissions. What I see as a misconception is that many think these have sliding gears that crunch into engagement. The ONLY gear that slides into engagement is reverse. ALL other gears are constantly meshed together and are all spinning together all the time. The only difference between a synchronized transmission and a non synchronized transmission is that a synchronized transmission has the cone clutches that spin the gears to the correct speed for you to allow a smooth shift. In the non synchronized transmission, you have a sliding square cog that has to get to the correct speed before it will slide into the square hole of the next gear. This is what makes for the feel of the gear crunching into the next-when in actuality the gears are always engages and it is the cogged slider that is making the gear crunching noise.
I know-way to much information. Just trying to clear up a minor misconception. Good Luck, TomC
