I happen to have some old 80-120 that has been sitting in the shed for a few yearsGear oil/ diesel fuel 50/50 mix in a weed sprayer,,, ruffly 2 1/2 gallons and lett'er buck...
Don't park in your driveway for 3 days to let the excess drip off...
2 X's a year for new vehicle,,, 3 or 4 X's for clunckers...
$20 ish bucks per spray,,, use cheap gear oil...
Actually i have both and my Ford is much better and way older than my GM lol!sounds like you have a GM?