Yes, your radiator has an ATF coolant portion (left hand side -- where you see the 2 ATF lines entering). IF this portion breaks, ATF could mix with the engine coolant portion of the radiator.
How badly is your coolant resevoir contaminated? Do you see droplets or chocolate malt-type gunk in there?
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi