Hate to reopen an old thread but I read spec's very carefully and buy on that spec. While I might have 10 different types of oil and greases around the shop, all my equipment seems to last a very long time with few mechanical failures. So, if Rural King, TSC, or NAPA has the lubricant that meets your needs, go ahead, save a few bucks. I tend to get my Mobil 1 at Walmart, my Castrol Motorcycle Oil (Actevo T4) at Cycle Gear when they have sales, Rotella at Walmat/TSC depending on price that week, Gear lube I get picky about and like the Castrol or Valvoline brand but often end up with housebrand from NAPA, or the local Friendly Local Auto Parts Store...But certainly if a vendor is selling off spec lubricants, they won't stay around long.
Howard