You can't mixed the two and won't mistake them either. Pentosin is green. ATF is red.
Read the label. You should be able to make out something. Below the label the bottle cap says ATF but do not go by that. The alternative is to do a complete flush and fill with ATF if you think Pentosin is too expensive and the car does not have self-leveling. The downside is ATF may cause some static steering noise in extremely cold weather when the car is cold. When the car is warm the symptom goes away.
'95 525i 5 speed, built 5/94, with a 93 m50tu engine
'94 540it built 3/93, converted to 6 speed with a 93 e32 m60 engine
'01 540it, built 6/01
'03 325i 5 speed, built 9/02
'10 mini 6 speed
Last edited by yaofeng; 12-20-2010 at 02:27 PM.