ToomanyVolvos;c-147790 wroteBetter than 3309? 3309 is not a brand it's a specification. Penrite has in the past claimed specifications it's doesn't have (read ZFHP6 6 speed special auto oil). Penrite is my most trusted brand, but correct specification is more important than brand. Mobil ATF3309 is supposedly the OEM product for Volvo as best I could read up, as much as I use Penrite for pretty much everything I'm a bit dubious about their synthetic ATF's claiming every spec under the sun.
It's a minimal level of performance in specific tests
The penrite fluid exceeds those requirements and is a better fluid
3309 is a medium quality mineral fluid its breaks down and starts failing to meet its minimum specifications far sooner than a good synthetic will
I've got penrite in my zf 6 speed in my BMW
100k km of absolute abuse and it's doing better than on the zf life fluid