Hello everyone I have been doing a lot of research on the transmission's reliance on the vacuum system because my 82' 240D started having flare ups on the shifts from 2-3 and 3-4. One worry I have is how long can I drive with these flare ups before it should be a concern? The only time I have is on the weekend and it worries me that I may be running the engine very hard. I have to really push the pedal down to get her to shift. When she shifts I can let up the throttle and settle her down. The same thing happens with the shift from 3-4.

The 2-3 shift flare up happens at around 33 mph.
The 3-4 shift flare up happens at around 55 mph.
Each of these shifts are soft.

I know the culprit is the vacuum. I have a vacuum gauge but I am going to purchase a mityVac to test everything. I have also heard that if I spray carburetor fluid or some other fluid around the hoses and whenever the idle revs up that is the general area where the leak is at (I think that is right but I want to check it through the mityVac for the experience)

Since my door locks have been acting up I am going to plug up the vacuum lines to the doors to try to isolate the problem in the door lock system.

She doesn't want to turn off on me after I have been driving around town never really going above 45 mph, so I have to turn her off manually using the stop lever. The thing here is I have to rev up the engine before pushing in the stop lever and the engine will cut off. This is another concern of mine, when should this be a bad thing?

There are a few things I know I have to do.
1. Check all vacuum lines and the main line should pull around 10-12 in. and should be zero at full throttle.
2. Make sure my T connector orifices aren't clogged.
3. Replace old hose connectors and hoses
4. Check vacuum diphragm
5. Replace shutoff valve
6. Replace Vacuum Valve : 3/2 Way
7. Adjust VCV and transmission modulator.

Is this right? What should I do first? How worried should I be? Is this thread too long? Hope I covered it all and thanks for all your help and the information that I have learned about my 82' from this forum has been amazing.

All comments greatly appreciated

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'82 240D
Currently running diesel but eventually I will French Fry her

Usually, vacuum leaks cause harsh shifting. But your other symptoms of shut-off problems definitely point in that direction.

Probably first would be fluid level. These cars seem to be very sensitive to this. Also bowden cable or shift linkage might need adjustment. Try here for checks and adjustments of the tranny:http://articles.mbz.org/transmission/adjust/

Hmmm, rev the engine before the stop lever works? The stop lever is a mechanical linkage on the IP. Maybe it needs adjustment?

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Sam

84 300SD 350K+ miles ( Blue Belle )

Thanks Sam

I'm going to give this a good look over.

I've also been looking at the Steve Brotherton article on the transmission and vacuum system pretty closely too.

I was still wondering if continuing to drive with my flare up condition is bad for the engine and how long can I do this until I should be concerned. Hopefully I can track everything down this weekend and have some replacement parts by that time as well.

Thanks again

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'82 240D
Currently running diesel but eventually I will French Fry her

Now that you have indicated there are other vacuum problems, I would either:
(1) Solve the other Door-Lock problems first and to do this you might start with my POST " W123 Vacuum DoorLock Diagram " at:
W123 Vacuum InterLock Diagram. Let me know via P.M. & I'll send you a quality copy of the diagram. OR
(2) Plug up the vacuum line to the Door-Lock system while you trouble shoot your tranny shift problem.

Funny, I don't remember contacting you before... must have been via this FORUM's P.M?? Altzheimers setting in I guess!!
Sam

Oh SD Blue's signature is Sam as well but I am definitely familiar with your Posts Samuel Ross because they have been most helpful.

Thanks for the info I don't kow when I will be able to get to work with an ample amount of time but I will try as soon as possible. I think I will definitely plug up my lock system to isolate the tranny problem and my door lock problem.

I will post as soon as I get some results

Thanks again

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'82 240D
Currently running diesel but eventually I will French Fry her

I could be wrong- but i would not do the carb cleaner thing on a diesel- it works fine with a gasser, but i dont think it will work at all on diesel- also a chance of causing a run away engine.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

Sam

Could I get a better copy of the door lock system sent to my e-mail address charlesabadam@yahoo.com

Thanks

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'82 240D
Currently running diesel but eventually I will French Fry her

This procedure is for gassers, where the vacuum is created in the intake manifold. It won't work on diesels, where the vacuum is generated by a separate engine driven pump.

Since the pump is not part of the combustion process, it won't cause a runaway. On a diesel, about all it does is waste carb cleaner.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Thanks guys I will definitely not do that

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'82 240D
Currently running diesel but eventually I will French Fry her

... this vacuum leak test of using "carb" cleaner I know from my " gaser days " might prove damaging to the artificial vacuum system on these diesel engines... and if you think about it, it's not that difficult to take a vacuum system [ one section/piece at a time ], isolate it by plugging/ capping it at one end and then see if it holds by pumping on it at the other using your "MityVac". Yes, it might take a little more time this way but these vintage cars respond well to a little " TLC " by gradually divulging to you a gradual understanding of how they work when you logically plod along.

And I for one have gained a new appreciation for the ingenuity of these various vacuum control systems… that is until where it is obvious the German engineers got carried away trying and meet/appease some of the “wacko” CA Air Resources Board requirements here in California... requirements that inevitably influenced the Federal MBZ car designs in these later years. Too bad they were not able to continue their more common " Keep It Simple Stupid " [KISS] design philosophy.
Still learning - Sam

Title of thread revised..........to comply with the open ended request of Samuel Ross.

Now you just have to come up with about 5000 different creative titles for oil threads.

Hello guys

I finally got to work a little bit on the problem with a friend with the same car.

We plugged up the hose connection to the door lock check valve with a golf tee and the car ran great and it is now finally stopping when I turn off the car and the flare ups stopped.

Now I know the problem is a leaky hose or connection in my dorr locking vacuum system. I will test all the hose connections and hoses to this system this weekend and isolate this prblem. Wish me luck.

I will post this new problem with a new thread.

Thanks for all of your help. See you next issue.

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'82 240D
Currently running diesel but eventually I will French Fry her

Sounds like you could use my fancy Vacuum Door-Lock diagram that is the subject of the following THREAD: W123 Vacuum InterLock Diagram

We tire-smoking 240D owners have to stick together... so if you will send your e-mail address to me at MrSafety2@Verizon.Net I will be happy to send you the necessary high-resolution diagram files(s) and one helpful photo on how to stop leaks at the 3-way and 4-way rubber connectors if they are not completely hard or cracked.

I trust you already have a vacuum hand pump with gauge ?

Sam Ross

Hello Sam

I actually already have your diagram I think you sent it to me eralier and it was a great help to me and my friend. We both diagnosed some problems with it. Thanks for making such a great diagram.

I will be working on my vacuum system tomorrow and narrow my search for the leaky suspect. I will definitely start a new topic when I feel lost.

Thanks again

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'82 240D
Currently running diesel but eventually I will French Fry her