I just changed mine a month ago and I used DextronIII
working fine
Penzoil rep. said it was ok to use in the older cars
mine is an 88 560sl
you can go on line and check the penzoil sight
If I had a newer year old benz I would use the factoy fluid
Also my friends also use it in their old 450sl"s
I think changing fluid is the important thing
old dirty fluid is the pits for a trans
My 2 cents

Mike