Hello all, I was looking at some bottles of gear lube I had lying around. One quicksilver bottle has gl-4. And a penzoil lower unit gear lube is a gl-5. Which one do I use for a mercruiser 1 drive. Serial number 4794847. It's a 233 mercruiser engine. I've seen some quicksilver bottles say for less then 75 hp. I haven't seen the ones for more then 75hp. Is there a difference between the two? Thank you.