Everywhere I read, people say to shift into neutral at a light, and some say just to hold the clutch in which I understand unnecessarily wears the throw out bearing.
Why can you not just shift to first and use the brake to keep the car from moving like all automatics in Drive, without touching the clutch? Is there something different about manual transmissions that makes the car stall when doing this? If so what is the difference?
Why can you not just shift to first and use the brake to keep the car from moving like all automatics in Drive, without touching the clutch?
In a manual gearbox, the clutch (when you release the clutch pedal) is a 'hard' coupling that does not allow any slip. So the engine will try to move the car against the brakes, it will lose that battle (brakes are more powerful than the engine), and the engine will stall.
In an automatic gearbox, the torque convertor is basically a box filled with oil and 2 impellers. One driven by the engine, one connected to the gearbox. The 2 impellers can have different speeds, so the engine won't stall when you stop the car, leave it in gear and use the brakes to hold it.
The advise to put the transmission in neutral at the light, and then release the clutch has been around for ages. There are arguments on both sides of the fence. I used to do that all the time with my cars and trucks. As I got older and arthritis on my left knee bothered me, I do it less. In fact the 99 VW I drive every day, I seldom put in neutral, except at a long light or a train crossing.
The idea was that the throw out bearing, which is under stress with the pedal pushed in, and the throw out bearing or release bearing is working with the pedal in.
If the transmission is put into neutral, and the pedal released, then there is no pressure on the bearing, and it will not wear.
For what it is worth, the current daily driver has 340k miles and is on it's original clutch, and I have not had to replace the throw out or release bearing.
So I am not really sure of the practical impact of all this, but I do sometimes take the pressure off the clutch and put the transmission in neutral at long waits, or where perhaps for safety reasons (hate to slip off that pedal and plow into the 9:22 Conrail).
EDIT ADD Ah, one more thing...there is a downside of putting the transmission in neutral all the time. First you are actuating the clutch twice, instead of once. Second, when you let out the clutch pedal with the transmission in neutral, part of the transmission starts spinning. This is twofold, in that the clutch just did a little work, but not as much as getting the car going, by getting the transmission turning. And the second related issue is that probably when you press in the clutch and put the transmission into first, you will do so quickly and servos (little brakes on shafts) will have a small amount of wear as they get things to match speed. Ancient transmissions may not have had all those servos, and had to be "double clutched" in some shifting operations.
Again, you might consider the neutral setting for longer wait times, or where safety is a consideration.
