Looking to buy used truck

[NoTruckYet]

Truck shopping.
2007 Volvo 670 just over a million miles. Dyno tested 40k miles ago, 1.8 blow by. . . so very low? Auto Shift trans, volvo engine. Current 2 truck owner bought for a relative to drive, put $14k in it to make it Level1 ready (passed New Mexico Level 1 a month ago), and family bailed out. Price? $25,000. Owner is clearly perfectionist, but still - million mile truck. Has intermittent transmission dummy light. Taking to mechanic for full inspection Monday, maybe even removing valve cover for inspection of cams. Seller not happy about this as he said he had valves adjusted 40k miles ago and 'it's all fine' but doesn't have pics. Does have receipt for work and dyno. Says dummy light on transmission is for low voltage on a sensor, but I am concerned that engine computer (new) might de-rate engine power just because transmission light on. Always nervous about someone who wants to grab your money and hesitant to have a thorough inspection paid for by someone else. Will need king pins, tie rod ends, and spring mount bushings in next 25,000 miles my guess (air bag front end).

Also went to Arrow Truck sales today. All trucks 500-600k miles for 70-90 thousand dollars, unless it's a MaxxForce and then $45,000 or so. They don't take oil samples for analysis unless you catch it being traded in before the PM and cleanup and then it's on your for cost (Blackstone Labs of Fort Wayne Indiana is my preferred lab).

Nearly everyone says "just buy new" but my absolute limit is $50k and that has to include everything to present to company where I will lease on. (They do own inspections and have high standards). They suggested buying a '13 or newer, or older is ok in VERY GOOD condition.

Please let me know thoughts - Thanks!

P.S. Rawze has tremendous videos and has prevented me from buying a couple of lemons already.