And get a Carfax history report, especially if you think something isn't quite right. Also, if you have a feeling that something isn't quite right, as if the seller is hiding something from you about the truck, then I would pay a mechanic shop to do a full vehicle inspection. Yes you might have to pay $100 or $200 to have a complete inspection done, but if you are paying over $5,000 for a vehicle it's well worth it. Combined with the fact that it's now an eleven year old Suburban with 175k miles on it, a full vehicle inspection would be a wise investment. Either way, you might be out $200 because the inspection revealed major hidden problems that will be far too costly, or else it will reveal several small but easily fixed problems. I'd rather be out $200 than to pay $5000-$6000 for a truck with a bad Transmission or engine or something.