TheSamba.com :: View topic - The Art of Double-Clutching

Tue Mar 02, 2010 4:38 am

Great write up...

But; I'm sorry. Seems like a big waste of time and energy, this double-clutching. Unless you are bored.

My VW Guru taught me that VW trannys will last a million miles easy. I'm no expert but in 20 years of Busin' and maybe 200,000 miles in a few Buses I've never had a single tranny-related problem whatsoever. And not only do I not double-clutch, but I very often don't even use the clutch to get out of gear.

So, just my personal opinion. And to be honest, I think I'd rather save myself a few seconds and leg-lifts a day and if it means a tranny rebuild every 500,000 miles so be it.

Tue Mar 02, 2010 7:22 am

Colin, very nice writeup. Somehow this one is much clearer to me than the first one you did. I understand much better the function of the synchronizers and how all the gears can be meshed at all times.

If I can suggest a revision for a future version, it is that I was still not fully clear how those three keys on the synchronizers function during a shift. Maybe a larger diagram or even a couple of photos might help.

Tue Mar 02, 2010 2:15 pm

ccpalmer wrote:
Seems like a big waste of time and energy, this double-clutching.
Unless you are bored.

My VW Guru taught me that VW trannys will last a million miles easy. I'm no expert but in 20 years of Busin' and maybe 200,000 miles in a few Buses I've never had a single tranny-related problem whatsoever. And not only do I not double-clutch, but I very often don't even use the clutch to get out of gear.

So, just my personal opinion. And to be honest, I think I'd rather save myself a few seconds and leg-lifts a day and if it means a tranny rebuild every 500,000 miles so be it.

I have visited hundreds of VW owners across this land. I have driven more VWs than I ever thought I would. Annnnnnnnnn lemmeee tell ya, I know a transmission that has been well-driven, and a transmission that has been half-beaten to death by only minor and chronic misbehavior on the part of the driver, not to mention the real spazzes. Why do some of the nice transmissions have two or three times the mileage of the beaters?

These transaxles must last us far into the future, at least for those of us who love these cars AND think ahead. If you look at the business that Darryl at AA Transaxle does, or Rancho, or any of the innumerable other transaxle rebuilders doing a good business in air-cooled Volkswagen transaxle rebuilding, you would hard-pressed to find any one of them who would agree with your VW Guru that "VW transmissions will last a million miles easy".

So, if double-clutching helps Other People's transmissions last, and it helps them become better-coordinated drivers, why not? I will challenge you to a race. The course will be a surface street that turns onto a steep driveway. We both will be equipped with a 1972 bus loaded with seven people and a shaggy dog, towing a boat.

The above is just an example of the pragmatic benefits of hitting 1st gear at 18 mph, bam now! and I promise you . . . it will take me far fewer "seconds" of your time.
Colin :P

Tue Mar 02, 2010 2:28 pm

ccpalmer wrote: I'm no expert but in 20 years of Busin' and maybe 200,000 miles in a few Buses I've never had a single tranny-related problem whatsoever. And not only do I not double-clutch, but I very often don't even use the clutch to get out of gear.

You do understand you've been blessed, right?

Tue Mar 02, 2010 2:32 pm

79SuperVert wrote: Colin, very nice writeup. Somehow this one is much clearer to me than the first one you did. I understand much better the function of the synchronizers and how all the gears can be meshed at all times.

If I can suggest a revision for a future version, it is that I was still not fully clear how those three keys on the synchronizers function during a shift. Maybe a larger diagram or even a couple of photos might help.

Well, I have to use words.
The keys are shoved sideways by the grooved sleeve when you shift. Their little nubs are spring-pushed into that orange striped groove inside of the center of the sleeve in the illustration. The force of your hand on the gearshift through the shift fork is what is pushing them sideways. They hit the synchronizer ring and push the ring sideways into the gear's conical friction surface. The taper of the gear's friction surface and the taper of the synchronizer's inner friction surface helps the keys generate serious grip for grabbing the gear. Then, once they are all at the same speed, the synchronizer teeth line up with the ones in the sleeve that was pushing all of this sideways all along. Here is what is interesting:
the instant the sliding sleeve is allowed to go sideways again, the nubs will jump out of the orange groove, the synchronizer loses its grip and that allows the pointy teeth to move just enough to get the synchronizer and the gear teeth started into the sleeves grooves. Have you ever felt your gearshift resist your hand, then you sort of wonder why it crunched at the last instant as though you were past the synchronizer? You were.
Colin

Tue Mar 02, 2010 4:40 pm

MrBreeze wrote: ccpalmer wrote: I'm no expert but in 20 years of Busin' and maybe 200,000 miles in a few Buses I've never had a single tranny-related problem whatsoever. And not only do I not double-clutch, but I very often don't even use the clutch to get out of gear.

You do understand you've been blessed, right?

:lol: Maybe; like I said I'm just relating my personal experience...

Colin - I will say I am really surprised by all the tranny-related problems I read about here on The Samba. Obviously it is an issue and like you say, we want these things to last another few millions miles... :D

So... I guess I'll have to figure out whether to change the tranny fluid on my '71... :roll:

Tue Mar 02, 2010 4:46 pm

ccpalmer wrote: So... I guess I'll have to figure out whether to change the tranny fluid on my '71... :roll:

Don't worry about it the guy, two owners back, probably did it already. Good for another decade or two for sure.

Tue Mar 02, 2010 8:28 pm

Wildthings wrote: ccpalmer wrote: So... I guess I'll have to figure out whether to change the tranny fluid on my '71... :roll:

Don't worry about it the guy, two owners back, probably did it already. Good for another decade or two for sure.

:lol: Always worked for me before! I just have to decide between dino and synth...