For what its worth I did my first change at about 28,000(ish) miles and before the J35 recall. The next one i went probably 32,000ish miles. 1st completely oil soaked. 2nd not near as bad. The J35 may have helped lot on this but I have no real proof on that other than eyeball. Could be coincidence though also but I don't believe in those.
Patrick

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2008 2WD 2500 QC Short Bed, 3.73, G56, PML Rear Diff Cover. Wheel to wheel 3" Nerf bars, AMSOIL Dual By-Pass AMSOIL In Crankcase, Tranny, and Differential