Just an update.

Got the power steering return lines replaced. So far so good.

Changed the oil and filter, now running Delo 5w-40 synthetic. Holy cow what a difference! Idles so much smoother when cold, noticeably more power when cold, etc. I can also report that my anti-drainback valve is working, the filter housing was full when I cracked the top off, draining quickly when I broke the seal.

Pulled into a different fuel station than usual today. "Sir, that's a diesel pump, you can't fill your truck there." Took a bit to get them to listen to me, they just kept repeating, "Move forward to a gas pump, move forward to a gas pump." For a bit I didn't think they were going to sell me fuel. Kind of rude, there's a reason they're not my usual station.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap