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Premium Member
1981 MBZ 240D 4-speed
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51 Posts
Discussion Starter #1
I took the 240D out for a drive today, about 80 miles, mostly on back roads near the coast. About halfway through the drive, when going up a slight grade, both in 3rd and 4th, it was as if the trans downshifted on its own and then upshifted when I let up on the accelerator. I could hear the RPMs change. I've never experienced anything like that with a manual before. I chose to take the flattest route home and didn't have any more trouble, even on the long Waldo grade coming out of Marin to the Golden Gate bridge.

Any thoughts? I really hope the tranny isn't going out on me.

Thank you.
 

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Premium Member
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496 Posts
Your clutch is shot.
+1. clutch slipping. It takes more torque to roll in higher gears, so that's where a clutch will first start to slip. It doesn't mean that you've -GOT- to do it today, I put another 10k miles on a car I got with that condition. It definitely will need to be done though.

Dave aka Ghan
 

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Premium Member
1981 MBZ 240D 4-speed
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51 Posts
Discussion Starter #4
Thanks. In the grand scheme of things, a clutch isn't that big a deal. Maybe Santa will bring me a new one. :)
 

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Premium Member
1967 250 SL, 1965 300SE lang
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3,063 Posts
Thanks. In the grand scheme of things, a clutch isn't that big a deal. Maybe Santa will bring me a new one. :)
If you've been really good this year, maybe Santa will install it for you.
 

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Premium Member
99 SLK230 Kompressor, 5 Speed Manual
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1,117 Posts
Yep, clutch time. If it's so bad that it's slipping plan on flywheel resurfacing and FOR SURE check the rear main seal.

In the case of the four cylinder manual transmission car, if you have a cherry picker or other way to pull the engine, it is every bit as easy to pull the engine for a clutch job as it is to leave the engine in place and pull the trans from below. In FACT I have pulled 240D engines for clutch jobs in LESS time than working from underneath.

In the case of a slipping clutch, there is a possible benefit by pulling the engine for the clutch job. That is that if you do indeed need to pay attention to the rear main seal, you will be able to remove the pan for seal attention, which cannot be done with the engine in the car.

The manual transmission 240D engine can be pulled and a clutch change done in about 4 to 5 hours. Another hour or so will take care of the rear main seal. These are REALLY sweet cars to work on, and this is a perfect example of that. Not many cars fall into the category of such an easy engine R & R.

Hope this helps.
 

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Registered
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56 Posts
This is a long shot, but try changing your fuel filters. I had a plugged up secondary filter on my 123 and it would only bog down in 3-4 gears. It felt frighteningly like my clutch was slipping as the car would lose power for just a second and come back.
 

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Premium Member
1981 MBZ 240D 4-speed
Joined
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51 Posts
Discussion Starter #8
Thanks for the all the information and advice. I don't have the facilities or capability to do something like a clutch repair myself, but I hope to one day in the not too far distant future. Ease of repair is one of the big reasons I ditched my 2009 Pontiac G8 GT for the 240D. Going from 361 HP to 67 is quite a change, but I don't worry about fancy expensive computerized parts failing anymore. And I won't even start on the difference in the quality of the materials used to build the cars.

The fuel filter is indeed something I'll check. I just switched to B100, and I'm anticipating 30 years worth of gunk loosening up and clogging the filters, but I didn't think it would happen quite this soon.

Thanks again.
 

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Premium Member
99 SLK230 Kompressor, 5 Speed Manual
Joined
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1,117 Posts
I'm right there with ya' when it comes to 123 diesel simplicity as compared to a modern gas engine car of ANY make.

If you hear the engine speed up in third & fourth when you are experiencing this problem, then it is indeed the clutch slipping. If you are simply loosing power without any engine rpm runaway, then it could be a fuel filter or several other things.

Hope this helps.
 

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Premium Member
1981 MBZ 240D 4-speed
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51 Posts
Discussion Starter #10
The engine speed definitely changes, so it does sound like the clutch is the likely culprit. I'm taking the car in next Monday. Somehow I think the car will get a more expensive Christmas present than i will. ;-)
 
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