BrendanC
$100 site donor 2024
Dex III as a whole shears out of grade very quickly. it is a great fluid and many high performance GM transmission builders require it be used but changed frequently due to the shearing. for daily drivers, dex VI will stay in grade much longer and require less frequent fluid changes. Yank converters requires the use of none synthetic dex III but i chose to run dex VI as i don’t want to drain and refil 4 gallons of trans fluid every other month. when they cut my converter apart for a cut and clean he said the clutches still looked brand new. Dex VI really is an improvement over Dex III unless you’re drag racing everyday.Would that be a problem with a multi vehicle dex 3s that are non synthetic only, or would synthetic multi vehicle dex3s suffer the same issue?
Mobil 1 atf has two synthetic variants. One that is recommended in older applications and meet dex 3H, while a newer model transmissions that meet dex hp.
For reference Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 (valvoline doesnt publish astm only mobil)
Maxlife starts out at 5.9
import starts out at 6.7
Mobil dex3h starts out at 7.4
Mobile dex hp starts out at 5.7
For completeness sake i lack of understanding of the differences between dex 3 vs dex 3h.