Anyone had issue with 991.2 GT3 gear stick

[neilsss2]

Just collected my 991.2 GT3 Manual yesterday.

All as nice as expected except I found that in 4th gear the gear stick ‘nudges’ forward (towards 3rd) when the throttle is applied.

Doesn’t happen in 2nd or 6th.

Anybody had anything like this (I certainly didn’t in 997.2 GT3 or GT4).

[Cheib]

Can’t help as I don’t have m8ne yet but would love to see pics!

[neilsss2]

[red997]

no sympathy - should have bought a PDK ;-)

I seem to remember a lot of cars exhibit this type of movement;
Whether its normal in a .2 GT3 I have no idea

[Skyway]

Just been out in mine and the gear lever doesn't move forward when applying the throttle in 4th.

[Taffy66]

Its the flexing of the gears when you increase the torque..The movement is not uncommon but whatever you do don't rest your hand on the lever when driving..If you hold the lever during driving you'll increase wear as the gear lever likes to give to avoid excess friction.

[Skyway]

Taffy66 said:

Its the flexing of the gears when you increase the torque..The movement is not uncommon but whatever you do don't rest your hand on the lever when driving..If you hold the lever during driving you'll increase wear as the gear lever likes to give to avoid excess friction.

Sorry but never heard of gears flexing and this is not something my car does. I have known gear levers to move when the throttle is applied when cars have a solid linkage to the gearbox and so move when the engine/gearbox moves. I believe this car uses a cable operated linkage which should reduce movement transfer.

[kilarney]

Its excessive gear endfloat not gear flexing which doesnt exist. Needs re shimming or in porsche case a new gearbox

[Taffy66]

Stop making a mountain out of a molehill as this behaviour is relatively common, and of no concern unless it pops out of gear..! Basically the gearlever is connected to the transmission,which is connected to the engine,which is connected to the chassis via FLEXIBLE engine mounts.Each time throttle is applied this flex caused by the engine mounts gets transmitted all the way to the gearlever.
Its possibly more noticeable at lower revs when the engine is slogging.Its only noticeable in fourth gear as this gear is in perfect straight alignment with the gearbox linkage..In other gears there is a slight angle which prevents the flex caused by the engine mounts being transmitted to the gearlever.
All normal and quite common on manual GT3s.

[Fish]

I think mine does it too, just normal movement of gearbox engine in mounts and only slightly. I'd only be concerned if it was dead easy to nudge out of gear or actually popped out of gear.

I've had a drink though so can't test it... Although I now want to go and thrash the car around.. Also good colour choice!

[neilsss2]

Thanks for all the (mostly) reassuring feedback - obviously hypersensitive to everything on a first drive

[kilarney]

Taffy66 said:

Stop making a mountain out of a molehill as this behaviour is relatively common, and of no concern unless it pops out of gear..! Basically the gearlever is connected to the transmission,which is connected to the engine,which is connected to the chassis via FLEXIBLE engine mounts.Each time throttle is applied this flex caused by the engine mounts gets transmitted all the way to the gearlever.
Its possibly more noticeable at lower revs when the engine is slogging.Its only noticeable in fourth gear as this gear is in perfect straight alignment with the gearbox linkage..In other gears there is a slight angle which prevents the flex caused by the engine mounts being transmitted to the gearlever.
All normal and quite common on manual GT3s.

Nah disagree can only happen as you describe if the inner and outer are not mounted to the same fixed point and as OP said didnt happen on any of his other cars that are also cable operated.
Its very common on many cars agreed and not really a problem unless it annoys but can only be reduced by removing endfloat as the gear rides up and down the helix moving axially then pushing the synchroniser /selector as the car moves from power to overrun. Ive rebuilt enough gearboxes to know this hence why I always set them up at the tight end of the tolerance range.

[IREvans]

Taffy66 said:

Stop making a mountain out of a molehill as this behaviour is relatively common, and of no concern unless it pops out of gear..! Basically the gearlever is connected to the transmission,which is connected to the engine,which is connected to the chassis via FLEXIBLE engine mounts.Each time throttle is applied this flex caused by the engine mounts gets transmitted all the way to the gearlever.
Its possibly more noticeable at lower revs when the engine is slogging.Its only noticeable in fourth gear as this gear is in perfect straight alignment with the gearbox linkage..In other gears there is a slight angle which prevents the flex caused by the engine mounts being transmitted to the gearlever.
All normal and quite common on manual GT3s.

Ah, as Kilarney stated, there's no such thing as gear flexing.

As the gearshift is cable operated, the powertrain can move as much as it likes, and therefore movement at the gear lever is isolated. The small movement noted is more likely torque takeup and a tiny bit of free play within the gears, amplified by the lever arm length of the gear lever. You've got to remember that say 200mm of throw at the gear lever, translates into around 25/30mm of throw at the selector, therefore 5mm of movement at the lever, equates to no more than 0.5mm of movement at the selector. I've built plenty of competition gearboxes (synchro and dog engagement) over the years to have experienced this phenomenon - its nothing to worry about.

[IREvans]

kilarney said:

Nah disagree can only happen as you describe if the inner and outer are not mounted to the same fixed point and as OP said didnt happen on any of his other cars that are also cable operated.
Its very common on many cars agreed and not really a problem unless it annoys but can only be reduced by removing endfloat as the gear rides up and down the helix moving axially then pushing the synchroniser /selector as the car moves from power to overrun. Ive rebuilt enough gearboxes to know this hence why I always set them up at the tight end of the tolerance range.

[Taffy66]

kilarney said:

Nah disagree can only happen as you describe if the inner and outer are not mounted to the same fixed point and as OP said didnt happen on any of his other cars that are also cable operated.
Its very common on many cars agreed and not really a problem unless it annoys but can only be reduced by removing endfloat as the gear rides up and down the helix moving axially then pushing the synchroniser /selector as the car moves from power to overrun. Ive rebuilt enough gearboxes to know this hence why I always set them up at the tight end of the tolerance range.

After that explanation it makes sense..I'm now more pleased than ever that i chose PDKS on my GT3..Can you elaborate why this movement only manifests itself in fourth gear and all but absent in the others.
Is this play due to variations in manufacturing tolerances, and if so it seems some cars have to suffer more than others as its within the spectrum of tolerances.
Am i correct in if this movement is noticed that its important not to grab the gearlever to avoid increasing pre-mature synchromesh wear.
Apparently this is a problem on some 991.2GT3 manuals in the US and after being examined by Porsche technicians they said the same as i did which is where i got this info in the first place as i'm no engineer.
Probably just another Porsche cover up to stop the punters demanding new boxes...!

Edited by Taffy66 on Thursday 8th March 12:41

[IREvans]

Taffy66 said:

After that explanation it makes sense..I'm now more pleased than ever that i chose PDKS on my GT3..Can you elaborate why this movement only manifests itself in fourth gear and all but absent in the others.
Is this play due to variations in manufacturing tolerances, and if so it seems some cars have to suffer more than others as its within the spectrum of tolerances.
Am i correct in if this movement is noticed that its important not to grab the gearlever to avoid increasing pre-mature synchromesh wear.
Apparently this is a problem on some 991.2GT3 manuals in the US and after being examined by Porsche technicians they said the same as i did which is where i got this info in the first place as i'm no engineer.
Probably just another Porsche cover up to stop the punters demanding new boxes...!

Edited by Taffy66 on Thursday 8th March 12:41

I am a mechanical engineer, and I wouldn't be worried about it.

[kilarney]

IREvans said:

I am a mechanical engineer, and I wouldn't be worried about it.

As I am and agreed dont worry about it

[kilarney]

Taffy66 said:

After that explanation it makes sense..I'm now more pleased than ever that i chose PDKS on my GT3..Can you elaborate why this movement only manifests itself in fourth gear and all but absent in the others.
Is this play due to variations in manufacturing tolerances, and if so it seems some cars have to suffer more than others as its within the spectrum of tolerances.
Am i correct in if this movement is noticed that its important not to grab the gearlever to avoid increasing pre-mature synchromesh wear.
Apparently this is a problem on some 991.2GT3 manuals in the US and after being examined by Porsche technicians they said the same as i did which is where i got this info in the first place as i'm no engineer.
Probably just another Porsche cover up to stop the punters demanding new boxes...!

Edited by Taffy66 on Thursday 8th March 12:41

As your interested.

Yes the play is always there but sometimes more or less dependant on how the various components in the assembly stack up ie the net of plusses and minus of each component. The net has a tolerance itself and less is preferred to a point just like differential backlash.
The reason some gears are worse than others is down to how each respective gear is shimmed and in this case 4th is clearly at the loose end of the tolerance band.
The reason you shouldnt leave your hand on the gear lever is that it can accelerate wear on the faces of the selector fork in the synchroniser hub because you are resisting it from finding its free running position.

I dont hold Porsche techs in the same regard I do the Engineers and unfortunately you seldom get to discuss with the Engineers and being in the oil game Ive heard some rubbish talked.

[Far Cough]

Worst.... "I've got a new GT3" post ever.......

Edited to fix non working smiley

Edited by Far Cough on Friday 9th March 18:33

[Taffy66]

https://rennlist.com/forums/991-gt3-gt3rs-and-911r...

Here's some useful info to the OP regarding issues with fourth gear.
Refer to post 19 on page 1 which the OP gives some feedback from his OPC in the US.

Edited by Taffy66 on Saturday 10th March 10:07