As you guys are probably aware, the "classic" Shell Rotella T that many of us know and love is gone and off the shelves in the states. I didn't believe it myself until I looked, and sure enough couldn't find the classic bottle, just T4. I guess some places still have the old stuff, but it's old new stock according to the store manager I spoke with when looking for it. I wanted to verify that "T4" was the new replacement which it does appear to be according to the T4 bottle, but it seems the entire T series (T4, T5 and T6) has undergone formulation changes; namely CJ to CK certification, and it's not playing too well with some bikes. I guess rekluse no longer recommends it according to this: https://www.vitalmx.com/forums/Tech...-T-15w40-now-called-Rotella-T4,1314916?page=1 Shell Rotella T was my go-to oil; literally used in all of my power equipment, from bikes to quads, to lawn mowers to log splitters. You name it, Rotella T was what I used for as long as I can remember in literally almost everything on my homestead. I loved it because it was good and was cheap, and I never felt guilty changing her out after 200 miles if I needed to. Has anyone here experienced problems with the oil after the formulation changes? Just curious... I have no idea what I'm going to switch to that's comparable in both price and performance.