Test drove the car cold. It ran nice, shifted pretty normal, a little delay in reverse, a good clunk when it does go into reverse, some flare between 2-3. Liked the car, liked the guy, closed the deal.

On the way home after 20 minutes on the highway I ran into some slow traffic, after making it through traffic the transmission would not shift into 3rd. I pulled over at a rest stop and cycled into park then back into drive, got back on the road, same thing, only now with a little harder shifting.

Had to bail out of I95 and onto RT1, the transmission really started acting bad, it started downshifting from 2nd into 1st at too high a speed (I was at this point limping along at 40 with my blinkers on). Then I lost all coupling - the engine revved to 4K and I pulled over - took it out of gear, then into park. Waited a moment, put it into drive and pulled thru an intersection to a gas station and checked the tranny fluid. It was so clean and new I could not see the exact level, but it looked wet up to the hot line.

I called the seller and told him about it - he acted surprised, said it had never happened to him and couldn't offer any explanation. We are at an impasse at the moment.

So - back to the transmission - I know the engines on the w124 well enough - but not allot about the transmission. With it acting like this, is the short answer a transmission replacement or are there other, exterior items to check first?

at least this one didn't start to run away after loading it on the trailler

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1991 300D

Well check the Bowden cable and vacuum line and the gear selector first - get a good fluid level reading with warm 80 degrees C fluid temperature.

Do you have pressure gauges to measure hydraulic pressure?

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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!

Do you still have reverse? If so that might point to a B2 piston failure as a possibility.

HA !! That made me smile for the first time in 90 minutes - thank you man.....

Did you ever find yourself a good wagon?

I do have a 15 PSI hydraulic gauge I was using for checking the fuel pressure - do you think 15 PSI is enough?

Tomorrow when it is good and light outside I'll do a better job of checking the tranny fluid - when I checked it earlier I was seeing red everywhere ;-)

Hey there Sir -

Here is what I have and the approximate speeds at which it does shift (I just took it for another run to better map out things)

Reverse - long pause after shifting - chunk, then reverse engages
From a stop -
First shift a little before 9 MPH
Second shift a little before 18 MPH
Third shift flares
Then no more shifting - I can get up to about 50-55 before I feel that the revving is too much.

I have seen this symptom before. Time varies a little but the transmission just disconnects. Not on Mercedes but the symptom seemed to occur after the transmission fluid gets up to normal operating temperatures. We just changed the transmissions so did not establish the cause.

It was just quicker and cheaper than pulling them apart. Let the transmissions cool down and they were good to go until warmed up again. So probably not that much an obscure problem and some member might know the cause. Probably a worn pump in the tranny was my thought back then.

Good to see you got your other project running!

At this point it could be anything really, partially failed/failing B2, pump failure, valve body issue, modulator(maybe sound a bit too drastic for that but you never know)

First thing to check is the Bowden, that it's intact and functional, then vacuum connectins, then fluid pressure. The pressure is checked with a guage that can measure the 60 PSI operating pressure. The guage is connected right near the modulator there is a bolt I'm pretty sure it's 12 mm. Get to a boneyard and grab an ALDA line on any turbo 617 car, you can use the banjo bolt and one of the line fittings to make up a test rig witha 100psi guage. The short bolt at the ALDA is best but the one at the rear of the engine on the manifold will work you'd just need to shorten it. Grab the copper or aluminum seal rings that are on the banjo bolt/fittings to reuse when you attach your test rig to the tranny.

good? no.

cheap? yes.

can I afford it? ehhhh

ironically its from the same town I got yours from...

still trying to decide if it is worth going down the rabbit hole again.

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1991 300D

Question for anyone. What are the symptoms when the Kick Down Switch or the Solenoid is stuck.

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84 300D, 82 Volvo 244Gl Diesel

15 PSI is enough for some of the lower pressure measurements - do the simple stuff first though.

If the fluid looks new then I guess it is a longer running problem that has just been "fixed" - but it is difficult to tell this for sure

__________________
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!

I think a pressure test is well warranted. Just remember you have to have the transmission up to temperature in your case to make it valid. When the fluid has colder heavier viscosity pressure will be higher. Because of the extreme delay you noticed going into reverse unfortunately I think the problem with that transmission is internal. Then again I know very little about automatic transmissions has to be a given as well.

I also of course cannot also claim the seller is a liar. My suspicion though is he may well be. . He is stupid enough to think someone will buy into your experience as being totally brand new. You could ask for a price adjustment based on the bad automatic. As the saying goes and depending on what you paid for the car it cannot usually hurt to try.

I only drove Spouse 30 miles or so during our time together but maybe a tranny swap would work out better in this case- you could send the new one out for a bench test/evaluation/rebuild.

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1991 300D

Quahog, Barrington has so much to offer you, doesn't it?

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 142k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife