SMG Grinding After Track Session

[eacmen]

This has happened a couple times before. Car is great on track, shifts are reliable and crisp. However when driving back to the hotel it will grind when coming to a stop. Now hearing periodic noises when changing gears even if engine isn’t running.

Gear actutator?

I recently relocated a rebuilt SMG pump to drug bin.

https://youtu.be/8Gqrefu3Uy4

[sapote]

Gears grinding like a beginner learns driving stick shift?

[eacmen]

Gears grinding like a beginner learns driving stick shift?

Yeah. I wasnt able to capture that sound on video. But yes that is what it sounded like when I was coming to a stop.

[oceansize]

After relocation mine makes the same noise. Nothing wrong as far as I can tell (and it's been a couple years) and for mine it is the lines vibrating. I think the noise either wasn't present and the longer hydraulic lines have introduced the vibration or when the under the intake next to the block the noise, and perhaps less noise, wasn't able to be heard over the engine.

[sapote]

Yeah. I wasnt able to capture that sound on video. But yes that is what it sounded like when I was coming to a stop.

Gears were engaged so the noise can’t be gears grinding noise.

[jet_dogg]

You know what the answer is.

[Da Jemster]

That's how mine sounded with my failed GPS.

[eacmen]

That's how mine sounded with my failed GPS.

Thanks! This is what I suspect. Is the GPS more than just a sensor? Is there something mechanical inside the GPS that makes the sound?

[oceansize]

I didn't notice the youtube link. That is different from what I experience from time to time.

[sapote]

Thanks! This is what I suspect. Is the GPS more than just a sensor? Is there something mechanical inside the GPS that makes the sound?

When it’s grinding, was it still with engaged gear? If it was engaged then a good or bad GPS was not the cause. Bad GPS only affects the shift and not after gear was engaged.
GPS for SMG is only an electronic encoder (Edited, was encounter)

[eacmen]

When it’s grinding, was it still with engaged gear? If it was engaged then a good or bad GPS was not the cause. Bad GPS only affects the shift and not after gear was engaged.
GPS for SMG is only an electronic encounter.

SMG was in A3 and coming to a stop. So trans was downshifting.

[sapote]

1. Now hearing periodic noises when changing gears even if engine isn’t running.

2. SMG was in A3 and coming to a stop. So trans was downshifting.

1. engine not running means noise is not gear grinding like a bad synchro or not total disengaged clutch. Is this noise same as the gear grinding noise or something else?
2. A3 is slow shift; do you think at faster shift mode, noise will change? There is no mechanical parts in the GPS for SMG as you asked previously. Maybe the slave cylinder needs to be bled and teach the computer again about the slave/clutch position.

[eacmen]

Update: I did an actuator and clutch bleed procedure and the noise remained. However, after running the SMG adaptations the sound went away. I did run SMG adaptations a week before the track event, not sure what would drift out of spec that would cause that noise though?

[sapote]

Update: I did an actuator and clutch bleed procedure and the noise remained. However, after running the SMG adaptations the sound went away. I did run SMG adaptations a week before the track event, not sure what would drift out of spec that would cause that noise though?

Maybe the TOB fork had moved too much -- worn clutch or worn PP fingers?
So this confirms that the noise indeed was the synchro gear grinding as the clutch not totally disengage causing the synchro failed to sync the two gears to be meshed.

[eacmen]

Maybe the TOB fork had moved too much -- worn clutch or worn PP fingers?
So this confirms that the noise indeed was the synchro gear grinding as the clutch not totally disengage causing the synchro failed to sync the two gears to be meshed.

Interesting … I recorded the SMG fluid reservoir while conducting the clutch bleed. When doing the clutch bleed it makes some strange sounds around the 12 second mark in the following video:

https://youtu.be/6geNFaTwFko

Does this sound indicate a bad TOB or clutch?