what is correct atf fluid on 1990 Mercedes-Benz 420SEL

what is coreect atf fluid for 420 sel and where does it get filled once drained

3 answers
The Correct Fluid for your German Made car Is Pentosin ATF 1. Made specifically for your car and lasted a long time between service intervals changes other fluids work but not as good. Electronic components such as Converter Clutches really respond to the Synthetic properties Of Pentosin ATF 1 No. A 0019892203. Info from My Mechanic In Germany. P.S. Can be purchased at your Local Parts house.
dextron or dex/merc3 ,$4 /quart as per my 20 year mechanic 1989-1990
Dextron ATF works just fine and you fill it in the dipstick tube.