HELP 82 240D Won't Shift Up To 4th

I've had this wonderful car for about 9 months and driven it about 12,000 miles throughout the northeast in that time. Odo reads 250,000 mi. Automatic tranny looks like a replacement and doesn't leak, slip, or clunk and goes right into reverse with no delay. But after returning from a 4 hour trip, I parked it for about 15 min. and then went to run some errands. Went through the local carwash and then drove about a mile to a store where I left it running while I was inside. Upon leaving there I discovered the prob. 1,2,3 seem OK.

When I first got the car I accidently knocked a vacumn line loose (the one off the brake booster tee) and it did the same thing (no 4th) until I reconnected, then all was fine. I can't find anything like that this time, including underneath at the trans. What coulda went?

Not an expert on MB auto trans, but have you tried driving in "S" and then shifting to "D" at about 45mph or so? Not sure what this would tell you, but at least you'd have manual control over 3rd and 4th.

Vacuum does not allow or prevent the transmission from shifting. That is not a vacuum control. Vacuum only allows for more comfortable, (softer) shifts. Sometimes drivers get confused. If it shifts 3 times, you are in top or 4th gear. If it only shifts twice, then it is most probably in third gear. But you don't have a tach, so all you have is the sound and feel of the shift. I just want you to be sure that it is only shifting twice. It should shift 3 times.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

Hi, and thanx so much for the replies. Fiddling with the shift lever doesn't help.

And I'm sure it's only going to third because there is no way it could go at highway speeds now- I don't dare go past 45 or so because of the engine RPM's.

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1982 240D Automatic - Rescued from 3 years in the neighbor's weeds...

I found this thread about a similar problem--that his 240D would only shift to top gear at way too high RPMs--

http://www.peachparts.com/shopforum/showthread.php?t=200767

This phrase in the thread may be helpful--

"from what I gather, the shift points are controlled by a cable hooked to the throttle linkage on top of the valve cover" --Magoo

This may help, although Magoo's car was a 300D. He goes on to suggest a search for a "vacuum diagnostic tool" to do vacuum system troubleshooting.

This explains about the throttle pressure cable Magoo was writing about:

http://www.mercedesdismantlers.com/722.3and722.416_transmission_adjustments#722.3%20Series%20and%20722.416%20Transmission%20Adjustments

Also try the DIY page: http://www.peachparts.com/shopforum/showthread.php?t=86871

I have no personal experience with any of this stuff, though...

I've had experience with the 4 speed MB tranny. My 4th was intermittant for a while with a sometimes huge flare, then no 4th. No matter what I did I had no 4th. 3000 rpm in 3rd at 50 mph. The last piece in the back of the case is the 4th gear clutch pack. The two teflon "O" rings that feed oil to it were worn out at about 245k. One of them was out half out of it's groove. Got a rebuild kit and a new B-2 piston and since most shops wanted 2k to tear it down, (one shop wouldn't touch it), I did it myself. Works like new.