Anyone use this stuff? Nissan oem synth 75W140 GL5. Going to do a rear diff gear oil change and found a Nissan TSB online that specs 75W140 for all Nissan vehicles (but don't know if it even applies to cars as old as ours). Only reason I'm considering it over a boutique synth fluid,is that awhile back I did a tranny fluid change and went with the Nissan oem MTF,and the shifting quality is literally a day and night difference over the boutique synth I had in there. My car has never shifted so smooth and precise.