too bad most forum members dont know that you can disconnect everything associated with emissions and tranny and just run vacuum to the vac modulator and then to the tranny modulator and youll have a perfect transmission. Dieselkraut taught me that when I put the motor in the sd, now the transmission shifts better than any old mb ive ever been in

I'm pretty happy with the way my '98 shifts. I'm also a die hard manual tranny guy so I frequently pull mine down a gear or two while slowing down. Mine has a lever position for all 5 gears and a switch to start in 2 if I so desire...

One day after the "newness" has worn off the car I may look into a 6 speed manual swap but I'm thinking that will be abouot five years down the road...

As far as one of the original questions is concerned, overdrive is usually 4th gear on a 4 speed auto or 5th and up on 5 speeds and above. It's literally a gear ratio numerically higher than 1:1, like .83:1 meaining the engine is turning slower than the driveshaft. Some people confuse this term with the automatic kicking down of one gear when the accelerator is pressed and call the resulting burst of acceleration "overdrive".

I believe the 'S' is for Sportiv and "L" translates into hill descent, but I need to look at the manual for the 300SD to be sure.

The 'S' locks 4th out of the transmission and 'L' gives you only 1st and 2nd
I would routinely run the SD in 'S' in town as it kept the engine in boost on the local roads... I would also use 'L' when making a point at a stop light:cool:

I have not played with the SDL's transmission yet as I am going to do a drain, flush and fill with synthetic soon.

Hey for what its worth, I believe that the 722 4spd is the original Hydromatic transmission developed back in the 1940's by Oldsmobile and sold to DB in the late 1950's for a transmission design that is almost sixty years old, they work amazingly well!
To adjust the shift points loosen the bowden cable to make the trans shift at a higher RPM, tighten to make it shift at a lower RPM

If there are kickdown switch issues, try lifting the carpet and making sure thet switch is clean and that the wires are not worn. I had to replace the wire from the switch because it was blowing the fuse when I pressed the button on the SD. Very annoying as it also cut power to the monovalve causing full heat


Oh yeah, 4th is not really a 'gear' it is direct drive through both planetary gear sets. That is why it is a 1:1 ratio. None of these came with an overdrive, which would be a ratio of say .83:1...

There was a great article in Hemming's Classic Cars about the original Hydromatic with exploded drawings and flow charts of the various functions. It is quite an engineering feat to have developed this, especially when you look at the rest of the auromatic offerings like the Chrysler Fluid Drive semi auto and the Buick Dynaflow...


Hope this helps!

Interesting, I suspect the 722's were a very old design. MB doesn't change much.

I sit too far away from the steering wheel to push the kickdown in.
I've been using the shifter like I'm driving a manual.
Glad to know I'm not killing the tranny.

For some reason I thought that S meant Slope, and put you in 3rd (well, 1st through 3rd), and L meant Low and locked you in 1st. I must have just guessed at what the letters mean because I can't find anything written that says that. But does L use 1st AND 2nd or just 1st?

I've been complaining about my transmission not being able to hold it in 2nd because when its cold, it'll shift right through 2nd and into 3rd, and I can't get it to downshift, just lugs along. I don't think my kickdown switch it working. But if L gives you 1st and 2nd, my worries are over.