2 quarts of M1 75W90 in diff.
Pan drop, clean, complete flush with 12 quarts of M1 ATF (older multi-vehicle formula) 2005 G35 100K
Looked like original fluid so I did 2 partial drains over the past 2 months with SuperTech ATF+4 and added 6 ounces of Auto-RX prior to complete flush. Magnets and Pan were surprisingly clean for 104K on original fluid.
Initial observations are that the vehicle shifts no differently with 65% ATF+4 and original fluid vs. 100% New M1 ATF.