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  #1  
Old 10-13-2002, 04:00 PM
300cd
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Double clutch

Can someone help me what do they mean by double clutch Thanks...

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  #2  
Old 10-13-2002, 04:09 PM
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On transmissions without synchromesh, such as most of the truck tractors in North America, in order to shift properly, you have to depress the clutch when shifting out of one gear, release the clutch while the shifter is in neutral, and then depress the clutch again before shifting into the next gear.

Part of the deal is that you have to match the engine revs to the new gearing, in effect, doing your own gear synchronizing. This you have to do while the transmission is in neutral, and the clutch out.

The second press of the clutch breaks the contact and allows the shift to be engaged (in theory) smoothly.

There are shortcuts, but that is how the textbook says it should be done.
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  #3  
Old 10-13-2002, 11:20 PM
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You can experience the purpose of double clutching by no clutching. If you match the speed of the engine with the speed of the transmission just right, you can pull the car out of gear easily. If you then match the speed of the engine with the new speed of the transmission you can slip the car into gear without using the clutch. The double clutching only makes the in and out parts a little easier. I would practice no clutching on an old beater before doing it on an expensive car. It a useful skill to have if your clutch goes out and you need to get home.
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  #4  
Old 10-13-2002, 11:50 PM
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Thank you very much for your info, I guess I don't have to double clutch too often since my tranny have synchromesh.
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  #5  
Old 10-14-2002, 02:30 AM
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I used to have to do it (slip it into gear without the clutch) on my '64 Jag when synchro bit the dust on 2nd gear. After a while it was easier and faster than using the clutch.

Made it much easier to learn later when I got my CDL.
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MB 1986 190D in my past
MB 1987 300E on the street
MB 1994 'Smoke Silver' E420 in my driveway
1999 Mazda Miata in the fun stable
1964 E-Type Jaguar Coupe- Sold
1970 E-Type Jaguar Coupe- Sold
1968 Corvair Monza Conv. with Turbo Transplant- Sold
1986 Merkur Xr4ti- abandoned
various mundane American autos

If I'd known then what I know now...

Hell, I'd probably still have done it anyways.
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  #6  
Old 10-15-2002, 04:16 AM
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When I first got my 240D it had a leak in the clucth master cylinder so I replaced it. On my first trip to town (50 miles of winding mt.roads)
it shifted fine.

As we were leaving town the slave cylinder blew leaving me with no clucth .I shut the car off then started it in gear I found second worked best.I drove it home rowing through the gears pausing in netural and modulating the throtle as you would in double clucthing.My brother drove his pick up for several months with out a slave cylinder,guess we are Oregon hillbillies ...........
William Rogers......
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  #7  
Old 10-15-2002, 05:09 AM
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Here's a question...how can you get the tranny to shift into the gear without grinding? I can shift from 1st to 2nd without the clutch on my pickup, but am afraid to try any other gear 'cause I don't want to break anything...or do you just put the gearshift at the point of entry into the gate and rev the engien 'till it wants to go in?

I use speed as a measure of when to shift my truck; at about 10mph I can go from 1st into 2nd...
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  #8  
Old 10-15-2002, 07:24 AM
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OK, I may be stirring up old (bad) blood here, but my 83 240D suddenly 'lost' the ability to go from 2-3 without severe grinding.
I have to double-clutch to get it in 3rd. This d-c method, however, does NOT work from 4-3!
Does this indicate that either my master or slave clutch is bad? (or is this my synchro? please say no.)

When I posted this a few months ago I got a lot of good, yet conflicting, advice. I have changed tranny fluid (Synthetic ATF, per the manual) and am now looking at the shift bushings. Is that even POSSIBLE that those could be my problem?

I am real eager to get this fixed as the d-c method is driving me nuts and I am only getting it maybe 3 out of 5 times without grinding!! ^@#$%!%

(My wife won't even try, just goes from 2-4...)

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