This doesn't happen all the time. It seems to happen for the 1st and 2nd gears at low speeds (15mph for 2nd).

Let's say I'm going 8-10mph on 1st gear and then i left go of the accelerator pedal. The car sometimes jerks back and forth. My thoughts are either the clutch is slipping a little - catching and slipping - or the motor mounts are shot and the engine is twisting enough to not apply a constant rotational turn on the clutch/tranny.

These are just guesses but I'd like to hear from others who know why this happens.

Thanks!

 

I am not sure what you are experiencing is abnormal. When this happens, slightly apply the clutch pedal to allow the engine rpms to increase. This should prevent the herky jerky motion.

 

yeah, it seems to happen on older cars. I can play with the gas or clutch to make it go away... just curious why it does it.

 

from what little i know, it tends to happen at slow speeds only. but it has been consistent with all the cars with manual trans that i've had. so i don't think it's an indicator of something wrong although i can't imagine it being good for your clutch. so i avoid such situations by making sure i don't do that in first gear.

 

Make sure you are going fast enough when you shift gears. Let off the Clutch slowly when taking off. I'm sure you would have more problems than that if the motor mounts were broken.

 

yeah, i think it's fine. I sometimes let go of the gas pedal without pressing the clutch cuz I'm trying to slow down just enough before taking off... minimize clutch depression plus there is no need.

i guess i'm more curious about the "why"... just trying to understand the mechanics behind why the car does that.

 

With a standard transmission the transmission and engine are directly connected via the clutch. On an auto, the torque converter replaces the clutch and allows slippage (why you can siton the brake at a stoplight without stalling). What you are feeling would be best described as "the engine idle is slightly slower than the current speed of the wheels" - so in essence the idle is trying to slow down the wheels, and the wheels are trying to speed up the engine" causing the springs on the clutch disc to compress/expand causing the bounciness feeling (see the springs in a pic of a clutch discbelow) -if these springs weren't there, you would wear/tear the friction material on the clutch disc since it wouldn'tbe allowed thatslight movementand would probably stall the motor.

My Camaro does it when I am idling in 4th gear about 30MPH in heavy stop and go traffic
My Prelude does it in 1st and 2nd just like the OP



[IMG]local://upfiles/29925/8F76917F65D64AD2B79D8CFE636F0E6E.jpg[/IMG]

 

Thanks for that info... what do the springs actually do? I can't really tell how they perform their function.

 

The springs are there so the clutchcan allow a"slight give" to prevent stalling, clutch disc/flywheel wear, and damage to the crank from being jerked excessively every shift.

 

Dont worry about it, its normal for manual cars to do that. It is pretty annoying though going from 1st to 2nd at higher rpms so I usually try under normal driving conditions to shift into 2nd like 1500-2000 rpm otherwise if im gunning it then I have to slam the clutch down fast when I let off the gas so it doesnt jerk back and lose me speed.