Dex is the ATF GM recommends. Transynd is the ATF Allison recommends. The change interval on Transynd is longer than on DEX. Transynd also runs cooler. Heat kills everything. Anything I can do to reduce heat is helping my stuff last longer.firehillbilly said:Is there that much difference? When I changed mine I put in Valvoline Dextron 6(?) which is fully synthetic. Same as GM spec.
And you would notice a temp drop with the AMSOIL Torque-Drive fluid as well. It meets the Allison TES-295 Spec..Duramax 6.6L said:I would use the Transynd for the Alison, Amsoil in everything else. When I put Transynd in I saw a temperature drop of about 30 degrees.