More gear selection issues - advice please?

[GregorJP]

So my car has decided that on the odd occasion, it doesn't like 4th gear when changing up very much and instead of selecting the gear, I get a horrible grinding sound and no gear (much the same as if driving a manual and selecting a gear without fully engaging the clutch). When it has happened, I've taken my foot off the gas, waited a second, selected 5th and it's fine. I can then select 4th again no problem.

Until the weekend, this had happened only 3 times in 5,000 miles and each time it happened on the track, under load and after a fair bit of track time. I assumed it was God's way of telling me to show more mechanical sympathy.

However, at the weekend, it happened just pootling down the road.

I've recently had a new clutch and flywheel, so I can only imagine it's a selector issue, but any ideas would be gratefully received. Cheers.

[DuncanR]

You mean like this ... http://www.youtube.com/watch?v=wg9q-lIgMsA&feature=channel

Murketts had mine in over a year ago now, I believe dear old Andy was still alive even so maybe longer, checked box, and said there was nothing wrong ...we need Gareth to give a view !

[CraigMillwardCroft]

That did not sound too good :whistle:

[shimmy]

same symptons with mine, changed box at Murketts as syncro going but catch early i reckon its just a selector issue


http://www.youtube.com/watch?v=NsfvmE-kD6I&feature=youtube_gdata_player

[DuncanR]

Yeah ..almost identical ...except my SB was going just a bit quicker than your SG one when it happened !:whistle:

[flow]

You need a new gearbox !

I changed everything on mine (2nd hand gearbox , acuator , pump) and it still had the same symptoms .
Then i bought a gearbox of a friends M3 (wich i knew was working perfect ) and now everything is fine .

[DuncanR]

You need a new gearbox !

I changed everything on mine (2nd hand gearbox , acuator , pump) and it still had the same symptoms .
Then i bought a gearbox of a friends M3 (wich i knew was working perfect ) and now everything is fine . Finally ! .... thats the only bit on Triggers Broom that heasnt been replaced yet ! And as you cant chip it , force it, make it go faster or generally bugger it about 9unless with some dodgy software) warranty shouldnt be a problem ! ... where is Elms number now ...:whistle:

PS - Dont forget all, once these babies are 10 years old, all bets are off anyway regards Warranty !

[CraigMillwardCroft]

Yeah ..almost identical ...except my SB was going just a bit quicker than your SG one when it happened !:whistle:
:hahaha::hahaha::hahaha:

[DuncanR]

I have booked whats left of my car into Elms for next Monday, but will probably trailer it over there sometime this week, probably Friday now, anyone else booked in ?

[GregorJP]

Ah, video brings back the exact god-awful sound I heard at the weekend. It's exactly the same as in Duncan's clip. Think I'll live with it as long as I can - it's only happened on very odd occasions so far...but I'll keep the group updated as it sounds like a common issue and I daresay a new gearbox will happen sooner or later.

[DuncanR]

Oh dear ... absolutely gutted ... I have to say farewell to my old gearbox the very last original large item left of the car other than the bodyshell !:( ...sadly its being replaced under warranty by a brand new one by ELMS;) .... what a class operation they run , with some really great people !:wink:

[Bounce]

Oh dear ... absolutely gutted ... I have to say farewell to my old gearbox the very last original large item left of the car other than the bodyshell !:( ...sadly its being replaced under warranty by a brand new one by ELMS;) .... what a class operation they run , with some really great people !:wink:Nice one Dunc.:thumbs:

[shimmy]

Nice one Dunc.:thumbs:

Welcome a new gearbox to the Register.:wink:

[conleth m3]

i have this problem as well. up until recently only happened as others have said, on track and when pushing on. happened abit more when on my ring trip at easter. took car to tom schirmer on kelburg who knows his stuff. he said you can try to bleed the clutch fluid, but didnt really know why it happens. he said it has happened on some of their race cars on one weekend, did nothing in between and was perfect the weekend after.

also, sorry dunc, he said a customer had had 2 replacement gearboxes under warranty and was still happening, and that bmw didnt know why it happened.

sounds like it should be something like a synchro or selector issue, but i dunno

has happened to me recently changing down from 5th to 4th as well, also from 3rd to 4th when not pushing at all on road in auto mode (level 2 - so not remotely aggressive) these times the car went into limp home mode for about 20 secs and also brought on smg yellow cog, which went out after turning ignition off and on again. hopefully has saved a fault code to give garage something to go on when in for a service this week

[giraffe]

i have this problem as well. up until recently only happened as others have said, on track and when pushing on. happened abit more when on my ring trip at easter. took car to tom schirmer on kelburg who knows his stuff. he said you can try to bleed the clutch fluid, but didnt really know why it happens. he said it has happened on some of their race cars on one weekend, did nothing in between and was perfect the weekend after.

also, sorry dunc, he said a customer had had 2 replacement gearboxes under warranty and was still happening, and that bmw didnt know why it happened.

sounds like it should be something like a synchro or selector issue, but i dunno

has happened to me recently changing down from 5th to 4th as well, also from 3rd to 4th when not pushing at all on road in auto mode (level 2 - so not remotely aggressive) these times the car went into limp home mode for about 20 secs and also brought on smg yellow cog, which went out after turning ignition off and on again. hopefully has saved a fault code to give garage something to go on when in for a service this week
if its happening on more than 1 lot of gear selection sounds more like a SMG pressure issue rather than internal box fault .

[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.