I agree with M.B.Doc. Several years ago I had the same thing happen to a
'94 model E320. I drained-flushed-drained-flushed-refilled and both the cooling system and the tranny survived. I put an external tranny cooler in front of the radiator with no adverse effects.
Good Luck!
Al

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2007 Mini Cooper 4K miles
1993 300E 2.8 120K miles
1961 Morris Minor 42K miles
1965 Morris Minor 23K miles
1997 Ford F150 235K miles
1987 Ramcharger 202K miles
1984 Chevy C-30 farm truck 88Kmiles
1968 XKE 59K miles
2001 Harley Softtail
2003 Harley Roadking