The '85 has 2.88 gears and can suffer a bit due to lack of available horsepower on hills.

It's imperative to hit the hill with an engine speed of at least 2800 rpm. This means that you've got to be moving 65 mph. That's a bit fast for climbing speed with the available horsepower, but, the alternative..........going 50 mph..........drops the engine speed to below the full available turbo boost and the vehicle doesn't have a prayer.

I've got a decent hill in CT that I can just barely hold 65 mph for the full 40 second climb. But, I'm the only one in the vehicle. If it had four people in it, it could never hold 65 mph and would lose speed rapidly once it fell below 60 mph.

Your solution should be to drop the transmission into third gear as soon as the engine speed falls to 2650 rpm.........about 60 mph. At that point, it will spin up to 4000 rpm and you'll have full HP for the hill. It will easily hold 60 mph for the remainder of the hill. Do not wait until it falls to 45 mph and finally does a 4-3 downshift itself.