Real crank seal leak advice w126 420SEL

[rickwomble]

My '91 420 SEL with 180K mi. started leaking oil profusely out of the hole in the side of the crankcase just in front of the cover plate on the drivers side that covers where the starter would bolt if it were on the Drivers side. The hole just goes through the case to the space where crank bolts to the plates that bolt to the torque converter etc.

What is the best way to determine the source of the leak?

I suspect the rear crank seal, but hate to pull the transmission off without eliminating any other possibility first. Ive been driving MBs for 25 yrs and never had a rear crank seal start leaking before.

What are my options?

Is there any other potential source of a leak in this location?

Any advice would be appreciated.

Thanks

Rick