Allison 653 Transmission fluid Needed Due to Leaky Hose

[Rich Farr]

Allison 653 transmission fluid Due to leaky hose, need to add transmission fluid to our 1979 Newell -6V92 DD with Allison 653 5 speed auto. Allison folks recommended new synthetic ($38.00 per gal), then dropped back to C3/C4 - ??

Don't want to mix synthetic in older unit and uncertain whether should use Dextron III or Type F. What readily available (old red) auto transmission fluid does Newell recommend for this unit? Thanks in advance.


Rich