Hi Guys
Newbie here. This is what I've got. A 1984 300D turbo Diesel, automatic with just under 300,000 miles. It has been sitting for about 6 months, I have started it about every 2 to 3 months (started Right Up) took it out for a drive and it ran find then I noticed that it was not shifting properly. It sat for about another month. Checked transmission fluid and added 2 quarts and took it out. It used to shift at about 2800rpms now for the lower gears it is shifting at about 4000rpms and the it is not shifting into the last gear. At 5000rpms I stopped did not want to press my luck, but it was doing about 65 mph. It has sat before, this is a second car (it will be my son's first)

I don't entirely know the symptoms of this but if the Kick Down Switch sticks it messes with the shifts; this is the one that if you press down on the Accelerator Pedal all the way drops you into a lower gear.

If you can't tell if it is sticking in the ON position trace the Wires and see if you can disconnect it at the Connector. I am guessing there is another Connector down on the side of the Transmission where the Kick Down Solenoid is.


It also might need to have the Transmission Filter changed. Unlike a lot of American Cars from the past that seemed to only have a fine mesh Brass Screen for a Filter the Mercedes actually has a Paper Element Filter.

Then there is the Bowden Cable that attaches on top of the Valve cover. That is supposed to adjust at what rpm the shifts happen at.

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84 300D, 82 Volvo 244Gl Diesel

Papalarge, welcome to this super forum. Also, say hello to the black magic that controls the transmission of your MB
From what you describe, my first feeling is that it's related to either the kickdown switch sticking or its the Bowden cable that got a bit rusty or out of proper adjustment.

First the kickdown switch . It's under the accelerator pedal and you will have to lift up the carpet beneath the pedal to see it. It's a small black plastic cylindrical device. Try pressing it down with your hand. The portion that sticks out of its body should get depressed when you press it and spring back to full height when you remove the pressure. If it's sticking, then it's for sure your culprit. You can try lubricating it with some plastic-safe spray lubricant (I think white lithium is safe for plastic ) . Else, you can replace it.
The only problem is that it's not necessary that if the switch is moving fine, the small solenoid its connected to at the transmission is also working fine. But since that takes longer to diagnose then the Bowden cable, you can leave it out as a problem for now.

The second step, if the kickdown switch is working ok is to check the Bowden cable. This part basically controls the upshift points of the transmission by doing some black magic. You can search for how to adjust and inspect it through the search forum and i am sure you will find a ton of information on it. Here is a video by a fellow forum member kindly put on YouTube that explains what all the mystery is

Mercedes Diesel Transmission Adjustment - YouTube.

My idea is based on a different chasis but I think that the same idea applies to diesel mb transmission of this era.

Good luck!

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1987 190D 2.5 Non-Turbo , automatic
Currently fixing : diagnosing vacuum functions,
, fuel leak at injectors, Dash Re-covering , speaker replacement with aftermarket amp and new wiring, generic keyless entry system .

Future projects :, antenna , Transmission modulator pressure adjustment or replacement... more to come...

Fixed : Windows, Ground wiring cleaning, random transmission kick-downs.

I had a similar experience and the problem was low on fluid. Double-check the level with the tranny well warmed up. Mine seems to be very finicky about the level and will start to flare in the 3-4 shift, if the slightest bit low.

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Sam

84 300SD 350K+ miles ( Blue Belle )

I just had this problem today. After flooring it to pass a car, the transmission would not shift back into a higher gear. Then I had problems getting out of first and second all the way home. Engine was running at about 4500 RPMs and it was still reluctant to shift. I had a hunch it had something to do with the kick down switch because it happened just after I floored it.

So, I just pulled the kick down switch and found it stuck in the down position. It is very tight to move it out of that position. I sprayed some silicone in it but it still does not return to the up position without me pulling on it. Is there some way to take it apart without breaking it, so I can clean and lubricate it? I am wondering if there is a rusty spring inside. I am guessing it has not been engaged for quite some time.

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85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

It is not cost effective to repair a $13.00 USD part...

Kick-Down Switch - on Accelerator Pedal
MB# 0015456314
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW


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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

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You are correct. I looked up the part and saw how inexpensive it is, and thought, "Why am I messing around with this?" In the meantime, I put some lithium grease where I could, chased it in with some silicone spray, worked it a bunch of times and it seems to be OK for the time being. But it is not 100%. I'll add one to my next parts order and will avoid flooring it until I get the new switch.

I did discover on putting the switch back in that you do not need to remove the whole carpet to get to it. It is right there under the accelerator pedal.

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85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

Buy a new one, chances are the contacts are burnt.....FYI.....its never a smart idea to spray a electrical switch with silicone lube or any other sort of oily lubricant.....it can cause arcing, non contacting....a host of other issues.....go to the auto parts store and get electrical cleaner and spray the switch out really good with that....pushing it in and out....it will clean it out and hopefully get it working again....another FYI my kickdown switch was 55$....yours is a bargain at 13$....

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