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I always assumed that my engine would do less work in N (neutral) than in D (drive). However, I tried a little experiment. My car wasn't moving, my foot is on the brake, and I have in D. I then switch to N, and to my shock, the RPM goes up! (Granted, it just went up by a little)

Doesn't this mean the engine is doing more work? Why would the engine do more work in N?

In all of the cars that I drove previously, the RPM always decrease in N. This is the first time I observed the opposite. (It is also the first time I'm driving a CVT (Continuous Variable Transimission), so I don't know if that has anything to do with it)

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A slight RPM increase when shifting from "D" to neutral is normal. The reason for this is the engaged transmission is putting a slight load on the engine and slowing it down. In neutral the engine is doing less work because it is not trying to turn the drivetrain.

  • I'm still confused. Can you elaborate what you mean by "the engaged transmission is putting a slight load on the engine"? Is this happening all the time? Or just during the switch to N? – Vivek Maharajh Mar 25 '15 at 16:46
  • It is happening all the time except when in park or neutral – mikes Mar 25 '15 at 21:51
  • Ah I get it. So when in P, it is engaged, and it puts a load on the engine, which makes the RPM go up? Sorry if I'm repeating what you said in different words, I just want to be sure I understand the answer? – Vivek Maharajh Mar 26 '15 at 4:14
  • @vivekmaharajh when car is in gear, it is spinning a torque converter, which lowers the rpm. When the car is in neutral, it only has to keep itself spinning, but it also has to be prepared if load is applied. If the RPMs were too low in neutral, it could cause the engine to stall when you shifted to drive. – MooseLucifer Oct 17 '16 at 14:37

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