Author Topic: Time to go from 1st to 2nd in manual transmission  (Read 7992 times)

ghenne

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Time to go from 1st to 2nd in manual transmission
« on: April 18, 2015, 09:21:43 »
I have a '65 230SL with a manual transmission. Taking it for a spring drive, I noticed I have to wait about 3 seconds before putting it into 2nd from 1st. I was thinking how much quicker the car could accelerate from the light if this time were shorter.

How long should it take? What can be done?

GGR

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #1 on: April 18, 2015, 11:48:06 »
Oh! By reading the title of your post, I thought you had been driving your car in 1st only and that you were now ready to start driving it in 2nd!

Could you describe more in detail what happens when you try forcing it shift faster?

It could be a clutch related issue (or its actuation) or a transmission issue (wrong oil or worn synchro).

Is the problem more noticeable when the engine/transmission are cold?

Cees Klumper

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #2 on: April 18, 2015, 12:21:49 »
I read George's post to mean that the ratio of the first gear is too long, meaning before he has the engine turning enough RPM's for it to make sense to shift to second, 3 seconds pass by. With a shorter ratio, the car would accellerate quicker and second gear would also arrive faster. But I could be wrong.
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

GGR

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #3 on: April 18, 2015, 12:37:29 »
It could be understood like that too, though these MB trans are notorious for having a very short 1st. May be the rear axle was swapped for a 3.27, which on a 230 could indeed translate into what you describe?

ghenne

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #4 on: April 18, 2015, 15:51:58 »
It's the from when the engine has sufficient revs and I engage the clutch, until I can put the gear lever into 2nd. If I rush it, I grind the gears.

tel76

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #5 on: April 18, 2015, 18:13:34 »
From what you are describing a re-build of the gearbox is required, the synchromesh on that gear is badly worn, if you do not want the expense of a rebuild you could delay the inevitable by double de clutching and put up with a slow gear change.
Eric

GGR

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #6 on: April 18, 2015, 18:32:04 »
Looks like a synchro, indeed. Before a rebuild, try replacing the oil. These trans take ATF. Often mechanics put standard gear oil in there and the result can be a notchy shifting. ATF is more fluid so the synchro may grab the gear better. Worth trying before taking everything apart.

The other issue could be that your clutch actuation system is not working properly. If you have an internal leak in the master or the slave cylinders, or if you have air in the circuit, the clutch won't disengage 100%. It could also be the adjustment between the slave cylinder and the yoke. Symptom is also grinding while shifting, and difficulty to engage first with the engine running and car at a standstill.

George Des

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #7 on: April 19, 2015, 01:05:04 »
Yes sounds like gear oil was put in the tranny. I made this mistake many years ago on my ZF-5 Speed and that was exactly the result.

ja17

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #8 on: April 19, 2015, 02:58:28 »
Does your speedometer needle jump during deceleration and fall for a second during acceleration?
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

A Dalton

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #9 on: April 19, 2015, 15:29:22 »
 Agree with JA..

This would be first suspect on W113 manual trans syncro  complaints.

http://classicmotorsports.com/project-cars/1966-mercedes-benz-230-s/a-cheap-fix-for-our-transmission/

Cees Klumper

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #10 on: April 19, 2015, 17:12:59 »
Welcome back Arthur!
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

Benz Dr.

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #11 on: April 19, 2015, 17:31:29 »
Yeah, but I would have checked the oil in the trans for level or ATF when it was here two years ago so it's more likely to be any number of small factors that relate to age and wear.
What I have found during almost every rebuild is exsessive end play on the input shaft. It should be nezxt to .000'' but is often .030'' or more. That alone will cause the syncros not to work as well as they should. If it grinds going into any one gear ( up or down ) it will be that syncro but a lot of end play tends to make it much worse.

1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

ghenne

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #12 on: April 19, 2015, 21:43:04 »
Does your speedometer needle jump during deceleration and fall for a second during acceleration?

No - it behaves properly.

ja17

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #13 on: April 20, 2015, 04:40:45 »
OK ghenne,  Sometimes shifting problems occur when the slotted nut on the tail shaft becomes loose. But, when this happens, the speedometer becomes a little erratic also.  Check the cheap thing first, like the fluid and the clutch adjustment.

Nice to hear from you Arthur!
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

ghenne

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #14 on: April 20, 2015, 09:56:01 »
Thanks to everyone for your input. I'll report back on the solution!

ghenne

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #15 on: May 07, 2015, 18:15:40 »
Update: my mechanic pulled the transmission and had a look inside. Clutch looks fine, no metal parts in the oil.

Uh oh. 3 teeth missing on 1st to 2nd, 2 on 2nd to 3rd. The synchro rings are made of soft brass and are worn.

Any advice on replacing the synchros?

ghenne

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #16 on: May 26, 2015, 09:37:57 »
Here's a picture of my old transmission: 50 years old, 250,000 km. The synchro rings (the brass ones in the picture) are significantly worn and have about 1cm of play, both of which will contribute to the slow shifting I was experiencing.

We found a rebuilt transmission (thanks, Benz Dr!) and we'll have it in this week.

ghenne

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Re: Time to go from 1st to 2nd in manual transmission
« Reply #17 on: July 13, 2015, 17:59:14 »
The rebuilt transmission is in and the car is back home. Shifting is now tight and accurate, with no grinding. It feels great!

Thanks to Benz Dr. for a great rebuild!