My 1985 300d suddenly will not shift up past second , nothing unusual happened I was pulling out of a parking lot and the car shifted to second smoothly and then would not shift up at all , reverse is also fine , I limped to a nearby mechanic who has some mb experience, so far the transmission filter and fluid was changed and the kick down switch was unplugged, I have had a bowden cable that is somewhat broken and hard to adjust for a while now without causing problems .
Car has lots of power and good vacuum , could it just be a leak?
everything I am reading is either about , bad shifting , stuck in first or no gears
As I mentioned it shifts fine into second and will not go higher , I can drive around at 30mph just fine.
I live on and island where we do not have anybody who specializes in these cars so I need good information to take to the mechanic, help appreciated

If you have a broken Bowden cable then the necessary input to the transmission that sends information about the throttle position is missing / a bit dodgy. This isn't going to help.

I'd check the shifter bushings just in case (input selector in cabin to back of transmission on left hand side)

As this is a sudden thing I'd check for other loose stuff such as vacuum pipes too

Before you go any further though I think you need to check the fluid level - so engine on at idle - warm transmission fluid - level surface - dip stick out - clean dip stick - dipstick back in - back out - clean until you get a consistent and clear reading.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Look closely at the bowden cable would be best to replace it or at least stablelize it look under hood for something that unhooked cable holder ect. ect. I think I had same problem ounce with my 85 300SD and it was in the adj. Of bowden as mine is broke also but still works sometimes seems to shift into 2nd a little late at 2500rpm but for now I can live with it until I purchase the plastic adjusting piece on cable.

After adj the bowden cable as best as possible , the plastic is broken but I was able use the thread side to hold it in the bracket. I had also noticed that the small plastic clip that attaches the cable to a metal bracket as it heads under the car was loose , I did not think much of that until I read yuke's post , so I had my husband with the stronger hands clip it back on .
I took the car for a test drive at first it seemed the same , then I started heading downhill got going faster thought I would try putting it into neutral and then back into drive at a higher speed , it did not seem to do anything when I pushed the accelerator it seemed like i was still in second and them all of a sudden it was working normal . So I really do not know for sure what the fix was , was it just stuck and will it get stuck again , was it really the bowden clip ?
I am a little worried it will happen again. Anyone want to buy a very nice looking 85 300d with about 185,000 miles , everything is working , ( for now)
I love this car but living in Hawaii with this car is frustrating even when I can afford to have it fixed I do not have a mechanic .
by the way thanks for the help !!!!

You may have some sticking in the valve body inside the transmission. I would change the transmission fluid and filter and use some high quality synthetic transmission fluid to fill the transmission.