I have a 1995 Volkswagen Santana which is very similar to the US Volkswagen Quantum. This car uses the exactly same trans, a 3 speed automatic gearbox and recently i changed from Dexron II atf to Dexron VI atf. Using the Dexron II after running 10 miles or more was very common to get the radiator fan running about 6 or 8 minutes to cool down the gearbox after turning off the engine. It is a common feature among the automatic Santanas. Well, after changing the ATF to a Mobil Dexron VI atf this isn't happening. Doesn't matter if I run 10 or 30 miles the radiator fan stays running only about 1 minute after turning off the engine, nothing changed except the ATF. The only thing I can think of is that the new ATF is so much more efficient in thermal conduction that the radiator fan doesn't need to stay too much longer running, but I found nothing searching in Google to support this hypothesis. Can someone confirm to me if that does make sense? Thank you all.