Transmission Engagement

[KiloFTW]

Pretty sure this is driver error, but could someone explain why the car might rock back and forth after shifting into first as if the transmission hasn’t fully engaged? Its like the power is there, then it’s not, then it is, etc. Maybe I nearly stalled it?

Shifting into second resolves the issue.

Doesn’t happen often but I’m assuming I’ve timed something poorly when it does. My foot is off the clutch while it’s happening.

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[KiloFTW]

One thing to add. It might be a coincidence but it seems more likely to happen if there’s a depression in the road after a stop sign.

 

[submitaweasel]

Accelerating? Decelerating? Downshifting? Starting from a stop?

First gear is an astronomically high reduction ratio and the oem motor/Trans Mounts have quite a bit of give to them.

Edit: 3.643 for first gear with a 4.353 final drive. That's a 16.5:1 reduction.

https://acuranews.com/en-US/release...5201862a-2023-integra-specifications-features


If the gear wasn't engaging, you would hear the synchros grinding when you let the clutch out. A manual transmissions gears are either engaged or not. The clutch is the only decoupling mechanism.

My best guess as to what you're experiencing is called "driveline lash."

 

[KiloFTW]

Accelerating? Decelerating? Downshifting? Starting from a stop?

First gear is an astronomically high reduction ratio and the oem motor/Trans Mounts have quite a bit of give to them.

Edit: 3.643 for first gear with a 4.353 final drive. That's a 16.5:1 reduction.

https://acuranews.com/en-US/release...5201862a-2023-integra-specifications-features


If the gear wasn't engaging, you would hear the synchros grinding when you let the clutch out. A manual transmissions gears are either engaged or not. The clutch is the only decoupling mechanism.

My best guess as to what you're experiencing is called "driveline lash."

Shifting into first from neutral after a stop. Trying to accelerate but the car isn’t having it. No noises that I can hear other than the pitch of the engine going up and down in time with the lurching.

 

[submitaweasel]

Shifting into first from neutral after a stop. Trying to accelerate but the car isn’t having it. No noises that I can hear other than the pitch of the engine going up and down in time with the lurching.

Light, moderate, heavy throttle?

If it's light throttle and the lash starts it could be getting worse from rocking your body and foot into cycle with it. You using the word "lurching" leads me to believe that it is just driveline lash. And yes, the rpms will fluctuate with it as the engine is rocking back and forth on the mounts (and other components, axles etc do have some ability to flex as well.)

I'm not saying there's not something wrong with your car because, let's be honest, anything is possible with these cars being so new and having proved they aren't perfect.

 

[submitaweasel]

Do you hear any "clunks" or metal hitting metal sounds when it does this? If so, it could be a loose or broken mount.

 

[KiloFTW]

Do you hear any "clunks" or metal hitting metal sounds when it does this? If so, it could be a loose or broken mount.

Thanks for the info. no clunks or any concerning sounds. It is light throttle and your theory about the rocking affecting my throttle pressure makes sense. I don’t think it’s a car issue and happens quite rarely. Just happy to have a plausible explanation.

 

[submitaweasel]

Thanks for the info. no clunks or any concerning sounds. It is light throttle and your theory about the rocking affecting my throttle pressure makes sense. I don’t think it’s a car issue and happens quite rarely. Just happy to have a plausible explanation.

What's your previous manual transmission experience?

I have stories for days on bushings causing issues in specific scenarios. I found out my rx7 had a broken motor mount while putting solid mounts in.

 

[KiloFTW]

What's your previous manual transmission experience?

I have stories for days on bushings causing issues in specific scenarios. I found out my rx7 had a broken motor mount while putting solid mounts in.

Very little. This is the first MT I’ve owned.

 

[submitaweasel]

Very little. This is the first MT I’ve owned.

Ah OK it makes sense now. Yes, this is (likely) normal behavior; especially with the severe reduction with the first gear ratio in these cars.

You can minimize this with either being exceedingly careful with your foot movements or installing the lower "dogbone" mount that many aftermarket companies offer.

 

[BKK Jack]

Very little. This is the first MT I’ve owned.

With this in mind it sounds like you probably just don't quite have your technique quite dialed in yet. Typically, manuals lurch when starting from a stop, because you are letting off the clutch a little too quickly with not enough rpms. Sounds like you just need more time behind the wheel (oh NO!) to coordinate your clutch and gas pedal inputs.

In the beginning it's better to err on the side of too much gas with a little more clutch slip. Not only is stalling and/or lurching embarrassing, but it also introduces shock into the driveline that can be much more damaging than a little clutch slip.

 

[Integra23]

My issue is having a smooth shift from 1st to 2nd. With the lack of pedal feel, I never seem to hit it quite right.

 

[RUNN1N]

Very little. This is the first MT I’ve owned.

You may also find the first-gear-start-from-stop experience is more pleasant/reliable with Autostop turned off.

 

[KiloFTW]

My issue is having a smooth shift from 1st to 2nd. With the lack of pedal feel, I never seem to hit it quite right.

I’ve learned that shifting at lower rpms or waiting for the rpm to drop, smooths my shift into second. I believe the latter is related to rev hang.

 

[KiloFTW]

You may also find the first-gear-start-from-stop experience is more pleasant/reliable with Autostop turned off.

If you are referring to the automatic engine stop when in neutral, I’d agree that it made learning this thing harder. I’ve developed a habit of leaving the clutch in until I’ve decided whether I’m going to be stopped long enough to kill the engine.

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