At least the pan can be taken off and dealt with on the bench or in a shop. I hate playing blacksmith when parts are still on the car!

For the torque converter try a different 5mm allen wrench. Yours may be worn with a rounded tip. Grind some of the tip down to get sharp corners. Clean the bolt hole of any crud that can prevent total engagement.

I believe the aluminum washer is the problem. It galls readily. I'll have to remember to replace it with copper next time.

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95 E320 Cabriolet, 159K