Author Topic: Automatic Transmission Issue?  (Read 1793 times)

Nero

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Automatic Transmission Issue?
« on: September 27, 2020, 12:52:32 »
Just wondering whether anyone has experienced this problem ? Recently I had the transmission fully reconditioned on my 1969 280SL RHD. Gernerally I am happy  it runs smoothly - perhaps  a little harsh in low gears occasionally but the main problem is when I have slowed right  down to turn a corner and the gearbox struggles to find the gear as I accelerate out of the corner at very slow speed. If I take my foot off the throttle , wait a couple of seconds then all is fine and I can accelerate away in gear . This happens mostly when the engine is cold . The engineer who has worked on many mercedes classics is struggling to resolve the issue so I thought I'd ask if anyone in the group has experienced this gear slip

Jonny B

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Re: Automatic Transmission Issue?
« Reply #1 on: September 27, 2020, 14:28:02 »
As a matter of fact I have, but really never tried to deal with it. It is not consistent, but I have not noticed that it happens mostly when cold. I think I have conditioned my driving to not jump on the throttle from a corner around town.
Jonny B
1967 250 SL Auto, DB 568
1970 280 SL Auto, DB 904
1966 Morris Mini Minor

JamesL

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Re: Automatic Transmission Issue?
« Reply #2 on: September 27, 2020, 17:28:44 »
Hello, and welcome to the group
Sorry I can't help  other than to say I've not had this issue and like Jon, I let the car warm through before accelerating hard.
James L
Oct69 RHD 280 in DB906 with cognac leather

Tom in seattle

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Re: Automatic Transmission Issue?
« Reply #3 on: October 12, 2020, 23:14:06 »
Mine will jump down and if I have much gas on it it will do so fairly hard and really jump.  I have fiddled with things but not eliminated it.  Mostly when cold .
Tom Averill
1967 250 SL Auto Euro Spec

JPMOSE

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Re: Automatic Transmission Issue?
« Reply #4 on: October 14, 2020, 00:20:39 »
It’s no secret that the gearshift sometimes can be a bit crisp. Some of this has to do with being a fluid coupler versus a torque converter. However, the stumbling to find a gear is not normal. I’ll try to let mine warm up a little bit but primarily this benefits the engine as the transmission hardly warms up until you actually drive it.  If your transmission was recently reconditioned, I would contact the shop that performed the overhaul and explain what’s happening. Also… I would continue to do research because there is a lot of information about these transmissions as they were used on several 1960s Mercedes. Did the shop have a lot of experience with vintage Mercedes? I hope you figure this out and I wish you the best of luck! I’ll be anxious to hear the outcome.
Best Regards,

J. P. Mose
1968 250SL
1970 280SE 3.5 Cabriolet
1987 560SL

Cees Klumper

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Re: Automatic Transmission Issue?
« Reply #5 on: October 14, 2020, 01:19:25 »
My '69 280 SL auto trans behaves very well and exhibits none of this behaviour, cold or hot. It would be good to find out the cause of this issue, considering how many replied with the same problem.

I did notice that, after my engine was rebuilt, it doesn't shift down as well as it did before - probably the result of more or less vacuum from the 'new' engine. It's not so bad that I have tried to fix it, but the point is that these transmissions seem very sensitive to the inputs they receive, so it could be a matter of the (pressure) settings / adjustments?
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

Rahul

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Re: Automatic Transmission Issue?
« Reply #6 on: October 14, 2020, 07:32:00 »
I have just become the owner of a 280SL and am also experiencing these issues - both being sluggish when accelerating out of corners, and the sudden jump up under acceleration that slows down the engine considerably.

In most corners I find it more predictable to shift the gearstick into '3' to ensure I get the power.

Sounds like I need to have that looked at then!
1971 280SL auto #571 over parchment