I drained and added two qts of RedLine D4 ATF the other day. D4 is an advanced ATF using polyol ester Group V base stocks. It is formulated to meet the proposed Dexron 4 specs, which means it exceeds Dex III and Mercon V. All the new ATF's have improved wear protection and flow performance at low temps, and in auto trannies eliminate the dreaded "shudder", which is caused when adjacent materials are spinning at different speeds when they should be in synch.
The T56 really likes this lube. Shifting was slicker, very positive, and I swear that the 1st gear buzz/whine was reduced a bit (is it the input bearing design I wonder?). TTC recommends Dexron III, so a higher performing ATF is sure to be completely compatible, undetctable to warranty snoops, while the strength of the ester-based D4 should provide exceptionally long service life and wear protection. Well worth it - highly recommended.
Oh - before you respond and say the tranny takes 3.8L, keep in mind that that is the dry fill spec - a lot of fluid stays in the tranny during a routine drain, so I may just redo this in a year or so so I end up with 80+% Red Line, rather than the 50% or so I have now. Could only get better.
The T56 really likes this lube. Shifting was slicker, very positive, and I swear that the 1st gear buzz/whine was reduced a bit (is it the input bearing design I wonder?). TTC recommends Dexron III, so a higher performing ATF is sure to be completely compatible, undetctable to warranty snoops, while the strength of the ester-based D4 should provide exceptionally long service life and wear protection. Well worth it - highly recommended.
Oh - before you respond and say the tranny takes 3.8L, keep in mind that that is the dry fill spec - a lot of fluid stays in the tranny during a routine drain, so I may just redo this in a year or so so I end up with 80+% Red Line, rather than the 50% or so I have now. Could only get better.