| Author |
Message |
MichaelETP
Guest
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 Posted:
Wed Nov 23, 2005 9:04 am Post subject:
kicking out of first |
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Hi everyone I have what I think is a problem on a 5 speed '90 535i.
On occassion when I start off after being stopped there is a loud bang
and the shifter is thrown out of first. This happens as I am letting
the clutch out.
If I give sufficient throttle and let the clutch out quickly it
doesn't happen.
Is this normal?
Thanks
Michael
Thanks
Michael
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ReddDawg
Guest
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| Posted:
Wed Nov 23, 2005 9:13 am Post subject:
Re: kicking out of first |
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| Sounds like a synchronizer going out allowing it to slip out of gear. |
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Jeff Strickland
Guest
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| Posted:
Wed Nov 23, 2005 9:14 am Post subject:
Re: kicking out of first |
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"MichaelETP" <metp@rogers.com> wrote in message
news:bom7o1t1s9ed8kvrfp45sdj35uofu1s79d@4ax.com...
| Quote: | Hi everyone I have what I think is a problem on a 5 speed '90 535i.
On occassion when I start off after being stopped there is a loud bang
and the shifter is thrown out of first. This happens as I am letting
the clutch out.
If I give sufficient throttle and let the clutch out quickly it
doesn't happen.
Is this normal?
|
No. It doesn't sound normal at all.
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Dodgy
Guest
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| Posted:
Wed Nov 23, 2005 4:58 pm Post subject:
Re: kicking out of first |
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On 22 Nov 2005 20:24:03 -0800, "ReddDawg" <jpummill@midsouth.rr.com>
waffled on about something:
| Quote: | Sounds like a synchronizer going out allowing it to slip out of gear.
|
Hmmm
IIRC the synchronizer or synchromesh purely aligns the teeth to allow
a smooth transition. Once the drive gear is engaged it plays no
further part until the next gear change.
If the synchromesh is worn, you'll get a grinding gear change from
teeth not messing as you try to select a new gear.
Jumping out of gear under load either means you've been grinding too
many teeth and have now damaged the gears, or your selector
fork/linkage has become damaged and isn't pushing the drive gear fully
into place.
Dodgy.
--
MUSHROOMS ARE THE OPIATE OF THE MOOSES |
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Jack
Guest
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| Posted:
Wed Nov 23, 2005 5:27 pm Post subject:
Re: kicking out of first |
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In a synchro transmission all of the gears are ALWAYS in mesh so there is
never any opportunity to 'grind the gears'. The gears that are not engaged
are however free to turn on their respective shafts and so are unable to
transmit power. The way a gear is engaged is to slide a splined coupling
into the gear. This coupling is always splined to the shaft and is splined
to the gear when it is engaged thereby making it possible to transmit power.
The spline teeth that engage the gear have two sections to them; a tapered
section that aligns the spline teeth as it engages and a parallel section to
transmit the torque after it is engaged. When you 'miss a gear' it is the
tapered section that tosses you out of the gear that you didn't quite get.
If the gearbox is abused by numerous instances of releasing the clutch
before the splined coupling is all the way home, the engagement teeth can
become worn and the parallel section becomes tapered thus tossing you out of
the gear even though the coupling is all the way engaged. There is no cure
short of replacing the sychros so it is probably time to start shopping for
a used gearbox. This kind of damage is often caused by a leaking clutch
master or slave cylinder that releases the clutch prematurely even though
you haven't taken your foot off the pedal so it would be a good idea to
check that before replacing the box.
"Dodgy" <Dodgy@earth.planet.universe> wrote in message
news:khi8o1da7ldfvomdkbvd480ibc1l1meoqb@4ax.com...
| Quote: | On 22 Nov 2005 20:24:03 -0800, "ReddDawg" <jpummill@midsouth.rr.com
waffled on about something:
Sounds like a synchronizer going out allowing it to slip out of gear.
Hmmm
IIRC the synchronizer or synchromesh purely aligns the teeth to allow
a smooth transition. Once the drive gear is engaged it plays no
further part until the next gear change.
If the synchromesh is worn, you'll get a grinding gear change from
teeth not messing as you try to select a new gear.
Jumping out of gear under load either means you've been grinding too
many teeth and have now damaged the gears, or your selector
fork/linkage has become damaged and isn't pushing the drive gear fully
into place.
Dodgy.
--
MUSHROOMS ARE THE OPIATE OF THE MOOSES |
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Malt_Hound
Guest
|
| Posted:
Wed Nov 23, 2005 7:42 pm Post subject:
Re: kicking out of first |
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Dodgy wrote:
| Quote: | On 22 Nov 2005 20:24:03 -0800, "ReddDawg" <jpummill@midsouth.rr.com
waffled on about something:
Sounds like a synchronizer going out allowing it to slip out of gear.
Hmmm
IIRC the synchronizer or synchromesh purely aligns the teeth to allow
a smooth transition. Once the drive gear is engaged it plays no
further part until the next gear change.
If the synchromesh is worn, you'll get a grinding gear change from
teeth not messing as you try to select a new gear.
Jumping out of gear under load either means you've been grinding too
many teeth and have now damaged the gears, or your selector
fork/linkage has become damaged and isn't pushing the drive gear fully
into place.
Dodgy.
|
Yeah. I think you are right. A worn syncro would not cause it to pop
out. Moist likely it's not going all the way in due to misaligned
shifter / linkage
--
-Fred W |
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Malt_Hound
Guest
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| Posted:
Wed Nov 23, 2005 7:50 pm Post subject:
Re: kicking out of first |
|
|
Jack wrote:
| Quote: | In a synchro transmission all of the gears are ALWAYS in mesh so there is
never any opportunity to 'grind the gears'. The gears that are not engaged
are however free to turn on their respective shafts and so are unable to
transmit power. The way a gear is engaged is to slide a splined coupling
into the gear. This coupling is always splined to the shaft and is splined
to the gear when it is engaged thereby making it possible to transmit power.
The spline teeth that engage the gear have two sections to them; a tapered
section that aligns the spline teeth as it engages and a parallel section to
transmit the torque after it is engaged. When you 'miss a gear' it is the
tapered section that tosses you out of the gear that you didn't quite get.
If the gearbox is abused by numerous instances of releasing the clutch
before the splined coupling is all the way home, the engagement teeth can
become worn and the parallel section becomes tapered thus tossing you out of
the gear even though the coupling is all the way engaged. There is no cure
short of replacing the sychros so it is probably time to start shopping for
a used gearbox. This kind of damage is often caused by a leaking clutch
master or slave cylinder that releases the clutch prematurely even though
you haven't taken your foot off the pedal so it would be a good idea to
check that before replacing the box.
|
Here's a better (and more acurate) description:
http://www.singster.co.uk/mascot%20mar-apr%202003%20(4).html
The key is in the "cone clutch"
--
-Fred W |
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Dodgy
Guest
|
| Posted:
Wed Nov 23, 2005 8:21 pm Post subject:
Re: kicking out of first |
|
|
On Wed, 23 Nov 2005 08:50:48 -0500, Malt_Hound
<""Malt_Hound\"@*spam-me not*yahoo.com"> waffled on about something:
| Quote: | Jack wrote:
In a synchro transmission all of the gears are ALWAYS in mesh so there is
never any opportunity to 'grind the gears'. The gears that are not engaged
are however free to turn on their respective shafts and so are unable to
transmit power. The way a gear is engaged is to slide a splined coupling
into the gear. This coupling is always splined to the shaft and is splined
to the gear when it is engaged thereby making it possible to transmit power.
The spline teeth that engage the gear have two sections to them; a tapered
section that aligns the spline teeth as it engages and a parallel section to
transmit the torque after it is engaged. When you 'miss a gear' it is the
tapered section that tosses you out of the gear that you didn't quite get.
If the gearbox is abused by numerous instances of releasing the clutch
before the splined coupling is all the way home, the engagement teeth can
become worn and the parallel section becomes tapered thus tossing you out of
the gear even though the coupling is all the way engaged. There is no cure
short of replacing the sychros so it is probably time to start shopping for
a used gearbox. This kind of damage is often caused by a leaking clutch
master or slave cylinder that releases the clutch prematurely even though
you haven't taken your foot off the pedal so it would be a good idea to
check that before replacing the box.
Here's a better (and more acurate) description:
http://www.singster.co.uk/mascot%20mar-apr%202003%20(4).html
The key is in the "cone clutch"
|
Yeah, I'm guilty of spending far too much time inside motorcycle
gearboxes, hence me almost stumbling into saying selector fork!
Dodgy.
--
MUSHROOMS ARE THE OPIATE OF THE MOOSES |
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|
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Jeff Strickland
Guest
|
| Posted:
Sun Nov 27, 2005 3:32 am Post subject:
Re: kicking out of first |
|
|
"Dodgy" <Dodgy@earth.planet.universe> wrote in message
news:khi8o1da7ldfvomdkbvd480ibc1l1meoqb@4ax.com...
| Quote: | On 22 Nov 2005 20:24:03 -0800, "ReddDawg" <jpummill@midsouth.rr.com
waffled on about something:
Sounds like a synchronizer going out allowing it to slip out of gear.
Hmmm
IIRC the synchronizer or synchromesh purely aligns the teeth to allow
a smooth transition. Once the drive gear is engaged it plays no
further part until the next gear change.
If the synchromesh is worn, you'll get a grinding gear change from
teeth not messing as you try to select a new gear.
Jumping out of gear under load either means you've been grinding too
many teeth and have now damaged the gears, or your selector
fork/linkage has become damaged and isn't pushing the drive gear fully
into place.
|
I agree. If the synch rings are the fault, then muchmore wear has happened
that is causing this problem. The synch rings shouldn't play any role in
keeping the gears engagde. If the gears are slipping apart, then they have
been abused to the point that they need to be replaced. The synch rings
could be seriously worn at this point as well, but that isn't why the gears
slip apart. |
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