Gearbox in gear while the clutch is in?
02-25-2019, 06:05 AM
#1
Instructor
Thread Starter
Gearbox in gear while the clutch is in?
Hey guys,
Bit of a weird question that cannot fit into the thread title.
My 993 C2 will sometimes have a weird issue when starting the car. The sequence of events is as follows:
Leave car parked on a slope.
Car is in gear and with the handbrake on.
I fully depress the clutch.
I turn on the ignition and start the car.
The car lurches forward or backwards as if I haven't put the clutch in.
Engine doesn't stall and ready to go.
There are no strange noises/grinding. The gearbox is otherwise normal. It doesn't seem to happen when parked on a level surface. I've gotten into the habit of putting the car into neutral to stop the lurch.
The slave cylinder and hose were replaced a year ago to stop a sticky pedal. The clutch is in need of replacement. It is a little tricky to modulate from a standing start and engages at the top of the pedal.
I'm thinking of getting a new clutch as the next service, but I'm wondering if there may be an issue with the gearbox that will require investigation at the same time.
So what do you think?
Bit of a weird question that cannot fit into the thread title.
My 993 C2 will sometimes have a weird issue when starting the car. The sequence of events is as follows:
Leave car parked on a slope.
Car is in gear and with the handbrake on.
I fully depress the clutch.
I turn on the ignition and start the car.
The car lurches forward or backwards as if I haven't put the clutch in.
Engine doesn't stall and ready to go.
There are no strange noises/grinding. The gearbox is otherwise normal. It doesn't seem to happen when parked on a level surface. I've gotten into the habit of putting the car into neutral to stop the lurch.
The slave cylinder and hose were replaced a year ago to stop a sticky pedal. The clutch is in need of replacement. It is a little tricky to modulate from a standing start and engages at the top of the pedal.
I'm thinking of getting a new clutch as the next service, but I'm wondering if there may be an issue with the gearbox that will require investigation at the same time.
So what do you think?
02-25-2019, 08:35 AM
#2
Rennlist Member
Parking Brake not holding and putting stress on transmission when in gear when parked on hill? Throw out Bearing going bad?
02-25-2019, 08:57 AM
#3
Possibly low on clutch fluid? Being on a slope could allow a small amount of air (compressible) into the line which would reduce clutch throw just enough. Admittedly just speculation as I am only focusing parking on a slope vs no slope.
02-25-2019, 09:15 AM
#4
RL Community Team
Rennlist Member
Rennlist Member
You may not need a clutch as your symptoms could simply be that the clutch master & slave need to be bled of air bubbles. This is especially likely in that you had that part of your car opened up recently for service and it may have not been fully bled-out as part of the replacement.
Also it is unclear to me how a slave cylinder could have anything to do with a sticky peddle. Can others chime in on this? As the original poster may need to find another servicing shop to work with.
Also it is unclear to me how a slave cylinder could have anything to do with a sticky peddle. Can others chime in on this? As the original poster may need to find another servicing shop to work with.
02-25-2019, 09:48 AM
#5
Rennlist Member
Force from the engine is somehow turning the transmission input shaft. It’s probably coming from the clutch or throw-out bearing. Perhaps the clutch isn’t getting fully disengaged due to air in the line or a fault system.
Sounds like the slave cylinder replacement from before may not have actually solved the original issue at hand?
Sounds like the slave cylinder replacement from before may not have actually solved the original issue at hand?
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02-25-2019, 02:01 PM
#8
Worth bleeding clutch line first then consider dry splines allowing a bit of clutch drag or spigot bearing (the one in the flywheel) is failing or pehaps has already, as can the release bearings in the throw out lever. Looking like a gearbox drop is imminent.
02-26-2019, 04:38 AM
#9
Instructor
Thread Starter
Thanks for your thoughts everyone.
I've had the car about three years. The pedal would often stick so I got the issue investigated. I expected them to change the master and the clutch pedal lever, but they changed the slave cylinder and the hose and that fixed the sticky pedal. The lurch issue has been happening since I bought the car, so I'd be surprised if it's a air/bleeding issue. That said, I'm not a mechanic and I was wrong about the clutch lever and master cylinder - so what do I know? :P
I live almost 4 hours drive from my Porsche garage so I need to plan everything before I get the car serviced. Hopefully it won't require major surgery or I'll have to walk home
I've had the car about three years. The pedal would often stick so I got the issue investigated. I expected them to change the master and the clutch pedal lever, but they changed the slave cylinder and the hose and that fixed the sticky pedal. The lurch issue has been happening since I bought the car, so I'd be surprised if it's a air/bleeding issue. That said, I'm not a mechanic and I was wrong about the clutch lever and master cylinder - so what do I know? :P
I live almost 4 hours drive from my Porsche garage so I need to plan everything before I get the car serviced. Hopefully it won't require major surgery or I'll have to walk home
02-26-2019, 04:57 PM
#11
03-01-2019, 12:34 PM
#13
Rennlist Member
Just curious what you found out? When I read this my first thought was air in the slave cylinder left over from the previous replacement that was maybe still trapped in there. Although depending on mileage/kilometers, or how the car was driven, perhaps it is time for a new one? In any case, start saving your $$ 
03-04-2019, 07:13 PM
#15
Instructor
Thread Starter
Hi all,
no diagnosis yet. I’m expecting to book the car in for an inspection at the end of next week.
I attempted to get video of the issue on the weekend and this was the best I could manage.
The car is parked on a downward slope and is being held by two clicks of the handbrake. Just enough to hold the weight of the car. As you’ll see, it starts to creep forward as soon as the engine starts. I wasn’t able to capture the sudden lurch that happens sometimes.
no diagnosis yet. I’m expecting to book the car in for an inspection at the end of next week.
I attempted to get video of the issue on the weekend and this was the best I could manage.
The car is parked on a downward slope and is being held by two clicks of the handbrake. Just enough to hold the weight of the car. As you’ll see, it starts to creep forward as soon as the engine starts. I wasn’t able to capture the sudden lurch that happens sometimes.