OK. I was generating a discussion and getting information on lubricating.
So, you have mentioned numbers, and synthetic vs non-synthetic.
Why not 30 wt? Does it sling all over the case and leave nothing for lubricating the gears? Does it get so hot it evaporates, only to reappear when it cools down? I don't believe my friend is cheap or ? He uses 30 wt and changes it every 3,000 miles (when he changes his oil). I like Castro oil. Don't know why, it seems to make a car happy. He is elderly and doesn't drive much. I will probably use this truck but not put on the usual 18,000 to 20,000 miles a year that I need to get to work.
Is 90 wt so heavy that it stays in the bottom, to lubricate the gears? Is that why it is recommended? Do you leave it in the transmission for 50,000 miles (saving time in O & M)? Or is it the choice of 'the book'? Which was written 40 some years ago. They didn't have synthetics back then.
And what about synthetics? In Minnesota it stays thinner. Would that be a problem in Texas? With the price difference of synthetic vs non-synthetic. Are synthetics better? I have so much money tied up in this 'old truck' - I wouldn't worry too much about a few dollars more.
Why do you use what you use?
Again, TIA
