Why I add 12% (one gallon) of gear lube at every oil change...

[JimT]

With these changing times I'm finding a need to change my engine additive gear oil. I've been consistently using the wally world SuperTech 80w90 and it's been good. But over the past months with all the shortages it's been hard to come by. My local store almost never has it and the closest one that does is a bit of a drive and not one that I prefer to visit (the kind that has a permanent police presence at the front doors). I used to order it online but they will no longer ship it.

I thought there was a thread somewhere that compared different gear lubes, but can't seem to find it right now. I do have a tractor supply nearby with their "Traveler" brand. They usually have some in stock but I wasn't sure if that's good for this application.

Also, short of having samples tested, is there any way to know if one of these brands (especially the store brands) changes their formulation?