T-400 fluid?

[ss3011]

All GM Dextron fluids at back compatible. The newer fluids, were developed as an improvement on past fluids, and are more stabile, and maintain their viscosity better, cold to hot. Part of the reason for the new Dex 6 fluid is to have a 100,000 mile service life in cars running normal conditions. Heavy duty driving still needs fluid swaps as recommended in the owners manual.