Saturday, November 11, 2006

Clutchless Shifting With a Manual Transmission

Recently, on a forum that I'm active on (GMI), there was a thread about whether people do/should downshift their manual trans-equipped cars to slow down (such as when approaching a red light). The thread developed into a discussion of other shifting techniques, and a mention of shifting a manual transmission without a clutch (I'm talking about a "regular" manual transmission, not an SMG or DSG clutchless transmission).

It is possible! Whether it's bad for the transmission, I don't know. I used to do it all the time in my Achieva SCX and my wife's Saturn L200. It's much easier to do when upshifting, when accelerating at a reasonable pace. You just let off the gas, pull/push the shift lever toward neutral (which it should do without any problem once the load is taken off the gears, since you've gotten off the gas), and then gently pull/push the lever toward the gear you want to go into. As the engine speed drops to the speed it would be in if it were engaged in that next gear, it should pop right into gear, no grinding. I tried this with my buddy's then-new 1996 Accord and I did grind the gears, so maybe it doesn't work with everything.

To downshift without the clutch, it's the same theory, but you have the blip the throttle a little, because the gear you're going into would need to be at a higher RPM for the speed the car is travelling.

One other tip - if your reverse gear is not synchronized (it wasn't in the Getrag transmission in my former N-bodies, but it may be in a new Saab), you can't put the car in reverse while it's still moving (or even immediately after pressing the clutch if the car was in neutral). But if you are impatient, you can just pull into first (or whatever other gear is synchronized) and then put it into reverse.

Is this bad for the transmission, as long as the engagement is smooth and there is no grinding? I heard that truckers do this all the time to save their clutch from some wear.

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