I have had my 140 for about 2 months and dearly love it. That being said, I need help. I have noticed on occasion it would not shift into 5th gear. I would move the shifter to the right and it would then shift into high. This has happened maybe 10-12 times over the last 2 months. Most of the time it shifts normally. I have put about 5,000 miles on it since owning it and it didn't seem like a big problem. I thought possibly a linkage adjustment or shifter bushings.I'm taking it to my indy next week for a trans service plus a couple other small things. Today about 50 miles from home, cruising at 75 on the interstate, I heard a "thump" kind of sound from under the car and it went from 5th to 4th and stayed there. I continued in 4th about 4-5 miles until I could get off. It seemed fine except 3400 rpm instead of the 2500 rpm I normally see at 75. I checked the fluid and looked underneath. Everything looked ok. I drove it home. It makes a slight "thump" sound when I take off and when I let off the gas and has it no 5th gear. I tried to research on the forum but couldn't find anything on this problem. Also, I'm not sure what transmission I have. The owners manual says it's "sealed for life" but mine has a dipstick. I researched the 140 before I bought it and the only transmission symptom I found was "clicking in reverse" which mine didn't and still doesn't do.
I'm sorry this is so long winded and I sure do appreciate all the help,
Ken

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Some days are like licking ice cream from a spoon, today is more like trying to staple jello to a brick!
1990 300 SEL

Its not sealed for life,Mercedes made a big mistake,now they advise chage fluid and filter every 80,000 miles.
The shifter has bushings which might need new ones.If its a 722.605 transmission,things like the conductor plate,might need changing.Or the wires go thru a rubber sleeve,that sleeve can go bad causing trans fliid to wick up,into the electronics.If you can't replace these things,a independant garage should be able to do thoose easy jobs.
Check Benzworld forum under w140 cars for more advise.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

Ken,

All I can say is the switch on shifter goes bad, and it can be fixed(or cleaned). Mine is a little wobbly, but works all the time...

I've not cleaned mine-up because the whole center console must be removed-meaning the radio and climate module need to come out(those use special keys to remove them). Then the plastic valence around the shifter has to be lifted carefully without breaking the locking tabs on the shifter..

Also, at the back of the transmission at the lip of the pan is black round connector with three wires(black, white & green). Push on the connector. Make sure it feels locked in. On the 1996 S320, the transmission is all Hydraulic except for fifth gear. The transmission you have is a 722.508

Best of luck,

Martin

Thanks guys,
Hopefully it's something electronic, that sounds a lot cheaper than a new or rebuilt transmission. With a little luck I'll find out tomorrow.
Ken

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Some days are like licking ice cream from a spoon, today is more like trying to staple jello to a brick!
1990 300 SEL

Download the master.pdf from post 26

no reverse / jerks in reverse when cold - Benzworld.org - Mercedes-Benz Discussion Forum

The document has a troubleshooting section.

I think if you can bypass the shifter overdrive switch, and simulate it with a external switch. I think that's where your root of your problem may be.

Best of luck,

Martin

Thanks again for your input, guys.
Martin, the link to the troubleshooting/repair article is great.
However, due to lack of service by the previous owner and me not attending to it quicker, the transmission is in it's final resting place. In it's place is an 80k used unit that has a new filter and is filled with new MB fluid. It also left a large dent in my wallet. I hope my experience will convince others to not put off servicing their 722.508 transmissions.
Ken

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Some days are like licking ice cream from a spoon, today is more like trying to staple jello to a brick!
1990 300 SEL

Ken,

I concur with your problem as it happened to me too, but I rebuilt mine myself with the help of this site, and others over a two to three year span. I was real greedy to give up my money because they saw the three pointed star drive in-So I banked my money, and learned a lot.

Glad you fixed your S320 as I run into a lot of these W140s for a transmission problem(which plagues the W140 series...). I like these land yacht's this is as closes as I can get to owning a boat...

Enjoy your car,

Best of luck,

MArtin