Yes, the fluid circuit between the tranny and torque converter is connected. The same fluid charge courses through both units.

Drain both, and measure how much total fluid comes out. If it's like my transmission (722.369), you'll drain about 7 qts.

After buttoning everything back up, refill the transmission with 4 qts of fluid, start the engine, then fill the remaining charge. This is the procedure written in the manual.

I suggest refilling ½-1 quart short. Then top off after a long hot drive when you have a chance to measure the fluid level hot.

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95 E320 Cabriolet, 169K