Are you saying you don't have a dipstick or you can't find it? Worst case - you could always measure what is drained out and replace the exact amount.

Have you tried searching on the fluid change procedure? It's been discussed before.

Hopefully your transmission is like mine. This is how I change the fluid....

The torque converter has a drain. You have to turn the torque converter until the drain plug is at the bottom. I believe a 5mm allen wrench removes the drain plug on the torque converter and pan. Drain both. You'll get about 7 quarts out of the transmission. Remove the pan, clean it, and replace the filter. I believe the pan gasket is reuseable. Button everything back up. Initially, pour only 4 quarts through the transmission fill/dipstick tube. Start the engine and let it idle. Pour in the remaining charge.

It's best to fill it short about 1/2 - 1 quart, then check the fluid level hot after a long ride and refill it to the proper level.

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95 E320 Cabriolet, 169K