Double clutching?

[montecristo]

Does the Vantage have a synchronized manual transmission?

Here's what happens... I'm doing 25-30, say; I shift up to 3rd gear and instead of it being a smooth transition, the car kicks forward (it doesn't lurch, it's just the feeling of a kick in the back). I'm told this happens in cars without a synchronized manual transmission, meaning I'd need to double clutch.

I went out in a completely different car to see if I'd somehow forgotten how to change gears, but no, it only happens in the Aston.

[Jon39]

montecristo said:

Does the Vantage have a synchronized manual transmission?

Here's what happens... I'm doing 25-30, say; I shift up to 3rd gear and instead of it being a smooth transition, the car kicks forward (it doesn't lurch, it's just the feeling of a kick in the back). I'm told this happens in cars without a synchronized manual transmission, meaning I'd need to double clutch.

I went out in a completely different car to see if I'd somehow forgotten how to change gears, but no, it only happens in the Aston.

I don't know what a 'synchronized manual transmission' is. However, when I do the gear change that you describe, as the clutch pedal comes back up approaching the bite point, if the engine revs are high for the matching gear box speed, there is a kick in the back, but if the revs are low, then there is the opposite feeling.

Sorry if this is all very obvious. Perhaps we will both learn more from the technical PHers.

[Cockernee]

Yes they are synchromesh gearboxes As every gearbox is in every manual road car since probably the 1970's or earlier.

Double de-clutching was a technique used by my Dad..........

If you have an issue like you describe, do you suffer any clutch slip? That sound like the clutch is not dis-engaging properly and may need sorting.

[DB9VolanteDriver]

montecristo said:

Does the Vantage have a synchronized manual transmission?

You can't seriously be asking this question. An Aston isn't a truck or a car from the 50s...

[divetheworld]

http://www.oerlikon.com/ecomaXL/get_blob.php?name=...

Spec sheet.

One of the reasons I love my new Sportshift box is the gearchanges. Using as an automated manual, I've managed to get a lot of joy from it over my previous manual.

Edited by divetheworld on Sunday 24th November 16:02

[snuffy]

montecristo said:

Does the Vantage have a synchronized manual transmission?

The last car not to have a synchromesh gearbox was one of these:



Are you joking I assume ?

[montecristo]

DB9VolanteDriver said:

You can't seriously be asking this question. An Aston isn't a truck or a car from the 50s...

Yes, McEnroe, I am seriously asking it. Granted, I just copy-pasted the long words from the interweb; what I'm really curious about is why I get this moderately unpleasant effect (especially on the passenger*, I imagine) only on this car.

(If the passenger is female and the kicking makes her think I'm an incompetent fool driver that she shouldn't be seen dead with, that defeats the purpose of luring her into the car in the first place, innit.)

[montecristo]

snuffy said:

Are you joking I assume ?

OK, OK, ignore the fact that I clearly know nothing about cars, and focus on the kicking please, people.

[With these feet]

Is it only 3rd it does it in? What are the load conditions to get it to do this? Under heavy/light accel/all the time?

Firstly I'd check the selector linkage on the top of the bos and make sure the nut is still tight. If its ok then....

When was the last time the transaxle fluid was changed?
One issue with these boxes is that the synchro ring blacken through use and stick to the gear rather than slide.

Im at Graziano in the morning, I will have a word with one of the guys and see what he suggests.

If the clutch was dragging it would probably be a little stiff to disengage and would be in all gears, not just 3rd IMO.

[montecristo]

With these feet said:

Is it only 3rd it does it in? What are the load conditions to get it to do this? Under heavy/light accel/all the time?

Firstly I'd check the selector linkage on the top of the bos and make sure the nut is still tight. If its ok then....

When was the last time the transaxle fluid was changed?
One issue with these boxes is that the synchro ring blacken through use and stick to the gear rather than slide.

Im at Graziano in the morning, I will have a word with one of the guys and see what he suggests.

If the clutch was dragging it would probably be a little stiff to disengage and would be in all gears, not just 3rd IMO.

3rd is where I notice it, maybe because I've just been city driving the past few weeks, so I don't use 4+ much. Revs is normal (2k-4k, certainly not 5k+). Acceleration is normal, in fact I think if I'm super revving, super accelerating (as much as you can up to 30mph), I don't get that kick.
Disengaging is fine. Engaging first from neutral is sometimes a problem (when it is, I move to second and then first in one move, that seems to work).
I've owned the car for two months, bought it with a 140 point check, so/but I can't say when the transaxle fluid was changed.

[snuffy]

montecristo said:

OK, OK, ignore the fact that I clearly know nothing about cars, and focus on the kicking please, people.

Ok then.

Are you letting the clutch pedal up too quickly ? For example, I used to have a Noble M12, and when changing gear (especially changing from 1st to 2nd) , if I let the clutch pedal return to the top of it's travel too quickly it would jolt (kick) - it was quite noticeable. The trick to a smoother gear change (in that car) was to being clutch up slower and increase the revs slightly. That would get rid of the kick.

Maybe take it to a dealer and let them drive it and see what they think ? If they think it's okay then it's most likely just your technique for changing gear; I reckon slightly depressing the accelerator when lifting off the clutch might solve your problem.

(As an aside, when I had an Esprit I sometimes would find gear changes a bit hard. It turned out I was not pressing the clutch pedal far enough. Being a short arse (obviously not as short as Jockman) I moved the seat as far forward as it would go (he has to use a cushion as well) and that let me depress the clutch fully - problem solved).

[montecristo]

snuffy said:

Are you letting the clutch pedal up too quickly ?

I'll play around with various release points. This is not the lurching you get from releasing way too quickly but still, it may help.

snuffy said:

...increase the revs slightly. That would get rid of the kick....

Good suggestion, I think increasing the revs does help, it just made me wonder why I need to do it in this car and not in standard cars.

[snuffy]

In general I find that normal/standard cars have very light clutches that need very little pressure. By contrast, cars like Astons, Lotus, Noble and so on have heavier clutches that need more pressure, so if you're not used to that it may feel not right. I've driven cars with heavier clutches for 20 odd years so I'm used to it (in fact, what feels normal to me may well feel not normal to other people). I suspect you just need to get used to the way it feels, that's all.

[erics]

Cockernee said:

Yes they are synchromesh gearboxes As every gearbox is in every manual road car since probably the 1970's or earlier.

Double de-clutching was a technique used by my Dad..........

If you have an issue like you describe, do you suffer any clutch slip? That sound like the clutch is not dis-engaging properly and may need sorting.

my 1973 fiat 500 does not have syncros on 1st and 2nd gear. Trust me, you would know instantly! You would not even have to ask...

[snuffy]

So how's the gear changing going then ? Is it your technique or do you think there's something not right ?

[montecristo]

snuffy said:

So how's the gear changing going then ? Is it your technique or do you think there's something not right ?

I've done some experimenting and I can't isolate the single factor. It happens at low and high speeds (within the range of a 2nd-3rd changeover), but mostly doesn't happen at all. If I release the clutch quickly, sometimes it happens, sometimes it doesn't.

If I release the clutch slowly, it doesn't happen. Which would be due to that, or due to something else happening in those extra two seconds, such as changing speed/revs. So fine, there's a solution, I'm just a surprised I get this in the Vantage and not other cars; maybe that's just to do with different bite points.

It's an interesting puzzle, but not a real problem. I'm putting it down to the car and I still getting to know each other>