More gear selection issues - advice please?

[shane@mbtech]

Duncans was different fault.

Possible snapped detent spring?, did you check Gareth.

[shimmy]

Mine was caught very early thanks to the video evidence. Was when gearbox was very hot :wink: and the day was very hot :wink: nd missed 3 to 4 three times in one (track) day.

I think AndyP got Gareth to look in the gearbox and there were signs of he synchro mesh going so a complete new box and never happened again. That was 40k miles ago.

I think Flow had similar problem and tried swapping everything from his box, actuator, controls etc and never cured it.

[giraffe]

Duncans was different fault.

Possible snapped detent spring?, did you check Gareth.

Not got box out yet , if i get chance to have a look inside i will all depends on how busy we are , as it warranty dont normally get to involved with stripping as not cost effective and its eayer for BMW to warrant a exchange box than have us strip and rebuild , bit of a shame really as like pulling stuff apart

[conleth m3]

if its happening on more than 1 lot of gear selection sounds more like a SMG pressure issue rather than internal box fault .

ok cool, cheers gareth. will get that looked into. my garage have a spare smg pump/actuator they said can try to see if helps. is the unit/fluid sealed for life or needing changed everyso often?

will it degrade over time, like brake fluid? just been bled but is it worth changing fluid of new?

cheers

conleth

[_Nathan_]

I have a complete CSL SMG system going spare if anyone needs some parts :thumbs:

[giraffe]

ok cool, cheers gareth. will get that looked into. my garage have a spare smg pump/actuator they said can try to see if helps. is the unit/fluid sealed for life or needing changed everyso often?

will it degrade over time, like brake fluid? just been bled but is it worth changing fluid of new?

cheers

conleth

Fluid its life time , if they change pump they will have to change fluid anyway , worth replacing salmon coloured relay first as altho its working it maybe poor contact causing to low current to run pump correctly .

[conleth m3]

Fluid its life time , if they change pump they will have to change fluid anyway , worth replacing salmon coloured relay first as altho its working it maybe poor contact causing to low current to run pump correctly .

ok will do

cheers mate

[thegingerninja]

Mine did exactly the same, grinds 4th on the upshift when hot. Detent springs seem to be responsible and it is always 4th gear that grinds the synchro. I had a new box under warranty. Once it has happened a few times, it will keep coming back - you need a new box.

[DuncanR]

Duncans was different fault.

Possible snapped detent spring?, did you check Gareth.

Dont you fookin dare Gareth ! ...stick that new box in lad ...Lawsy is delusional ! :hahaha:

Not got box out yet , if i get chance to have a look inside i will all depends on how busy we are , as it warranty dont normally get to involved with stripping as not cost effective and its eayer for BMW to warrant a exchange box than have us strip and rebuild , bit of a shame really as like pulling stuff apart

Exactly ! cant knock the Germans is what I say .... :hahaha:

[Bounce]

Dont you fookin dare Gareth ! ...stick that new box in lad ...Lawsy is delusional ! :hahaha:

:hahaha::hahaha:

[GregorJP]

Just to update everybody, went to Bedford the other weekend - didn't take it easy but only got one instance of grinding between 3rd and 4th. However, also got the gearbox warning light twice when the gearbox got hot. Once it had cooled down, it was fine. I fear that some work is in order..

[The Gorilla]

Hi,

On Hard Track Days with SMG
then a Gearbox Oil Cooler /Pump is
a given.

The lower you can keep the G/Box
temps [ie reduce thermal store]
then the less chance for parts
to go wrong.

Heat, can fuck parts just as quick
as your right foot.


Regards,

The Gorilla.

[cantfind1]

You don't need a new Gearbox!

As a few others on here have said briefly, take gearbox out and replace all the detent springs, from memory there a 4 I think.....

This will be the cause of your problems..one or more will be snapped or the spring has lost its tension....

Also worth replacing the little plastic nipple on the end of the selector fork as this will snap eventually as well, also check the selector knuckle is lubed and not rusted or corroded as over time it can seize especially if car is not used a lot...

As for the gearbox oil, change it.....it may say lifetime on it but in all honesty that is complete shit....

SMG fluid that runs through the pump is not lifetime though and should be bled and replaced as often as your brake fluid as far as I am concerned...

Good luck..

[GregorJP]

Awesome, thanks guys.