Adjusting Transmission

[J. Huber]

A recent post by Engineer got me thinking. For years, I have been defending our automatics against those who call them "jerky" or "clunky". My argument has typically been -- upshifting is more an art than a science -- and that I can move through the gears quite smoothly. This part is true for my car. But the fact is mine can be jerky from 2nd to 3rd to the "untrained" and even me on ocaission. Are there any basic adjustments that can be made to smooth things out? (i.e. without tearing the transmission apart!)...Thanks.

James
63 230SL

[TheEngineer]

Hey James: So I got you thinking! I shall mark that as my lifetime achievement! My transmission has become much smoother during the two years I have driven this car - about 5,000 miles. But still, very seldom now, the upshift is noticeable. The downshifts never are. But about one year ago, I drove a 280SL that was for sale by a local dealer: The transmission shifted very smooth, never as much as even a small jerk. Mine is like that too, but only when it is cold, in that, it has never jerked when I start my driving. But - like I said - when I have driven about 10 miles, it sometimes jerks from 2 to 3rd. More so, when I drive very gentle. No jerks when I push it: Then it upshifts at about 3500 RPM and the shift is always smooth. I have changed the filter. It required dropping the pan. I have adjusted the modulator pressure to the book and verified that the solenoid operates as it should. The modulator pressure was pretty much within tolerance. Recently I found a shop manual for the transmission and I plan to educate myself. There is not a lot of incentive because it shifts fine most of the time. But after driving this dealer's car, I am convinced that the transmission will shift very smooth. The observation, that it shifts smooth all the time when it is cold, leads me to believe that it is related to oil viscosity: The colder oil is thicker. There may be wear in places. The transmission is original to the car and the milage on the vehicle is unknown. My 2¢.

[nick350]

You could be describing my 280 gearbox, did you ever find out about the jerky when hot issue?

[J. Huber]

Hey Nick350. Well, the short answer has to be yes, I seemed to have remedied the "clunky & jerky" shifting. While not perfectly smooth, it is more or less as the Engineer describes his.

Here's the longer answer. In my case, it turned out to be less about the transmission itself and more about the throttle linkage and the position of the stop screw on the throttle intake. You may recall reading about how crucial this all is to idle, engine performance, and alas: shifting! I first made the adjustment to the idle stop, which helped the shifting immensely but left my idle all amiss. I then tackled the linkage, changing the bushings, ball-sockets, and getting it to it proper position. Things are basically all good now.

PS I was/am working off a transmission that has fairly recently had the filter & fluid changed -- and is kept at its proper level. I'd say that is an important part of the puzzle as well.

James
63 230SL

[merrill]

here is a great link on fine tuning the tranny's

http://www.mercedesdismantlers.com/16BoltInstallationInstructions.html

Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230