Dex 6 transmission fluid
A couple of years ago I pulled the transmission pan and replaced the filter. Since then I have done a few drain and fills of the fluid. I have found that Dex6 is getting harder to find. What seems ...
Forum Discussion
Well, for starters what vehicle are we talking about? I did a lot of research lately for the Allison transmission in my 2005 Chevy. As it turns out when GM switched from Dex3 to Dex6 they didn't realize that the Dex6 hardened the seals in the Allison and made them leak. They eventually discovered this and updated the seals but some trucks with the old style seals still left the factory requiring Dex6. Your not supposed to put Dex6 in an Allison older then about mid year 2006 or it will harden the seals. The go-to transmission fluid now for the Allison is Transynd which is a synthetic engineered by Castrol specifically for the Allison. If you buy GM fluid for the Allison now days it is supposedly rebranded Transynd. It may be a great fluid for your transmission instead of the generic Dex6 but I have no idea.
