Hello Viper,
The automatic transmission will take a little over 5 qts if you drain the converter also. It should be drained since most of the fluid is in there. Remove the inspection screen on the bell housing and rotate the converter until the 5mm allen plug appears. There is also a transmission cooler built into the bottom of the radiator. There is not much fluid here, probably not worth removing the line to drain. The sixteen bolt oil pan can be removed but be prepared to change the cork gasket and the transmission filter inside. While your in there make sure all the valve body bolts are snug. Do not over tighten the pan and cork gasket during installation. Add a few quarts of fluid before starting the engine. It should take over five quarts. The final fluid level should be read while the engine is warm and running. Move the shifter through the gears to circulate fluid. Re check level with engine running, making sure you are on perfectly level ground. Between the marks on the stick is about 1 pint! Re-check after test drive. If the fluid is above the top mark, I like to bleed some fluid off by loosening the transmission hose at the radiator.
Originally these transmissions used Type A fluid. Hard to find these days. A 1972 factory workshop supplement I have explains Dextron B can be used after new on these units. You may want to call the Mercedes Classic Center to see what their opinion is these days with the newer fluids. Good Luck!
While your doing fluids, check to make sure that upper internal rubber seal is still in place above your engine oil filter (often missing). Otherwise you will not be filtering all your oil!
Joe Alexander
Blacklick, Ohio
