I saw some gear oil on amazon that just said 80w. And it got me thinking why theirs no second number like the usual 80w90. I'm guessing their the same viscosity at cold temperature, but i'm wondering what the viscosity of the 80w is at high or operating tempurature.
CactiJoe
SAE-80 will just stay SAE-80 and will not get thicker when it gets hotter. Even a 80w90 will remain SAE-80 unless the temperature climbs closer to 200F.
Anonymous
It is a straight weight gear oil or mono viscosity gear oil. 80W is the operating temp viscosity. The cold temp viscosity is more viscous. Do not use it for your car if your car requires 80W-90.
Mark IX
I hate to do this to you, but you need to know that postings on Amazon aren't always perfect. I have no doubt at all that they should have put up 80w90, 80w makes no sense at all. A bit like all those question marks.