I’‘ve done quite a bit of homework on the H3. Spoke with a small family run repair shop that I trust and have used over the years. Sad to say they are retiring and closing up by the end of the year
Steve told me that the 3.7 I5 is a good little engine. He said it won’t win races, it’s not a powerhouse, fuel mileage by today’s standers is not great. But overall it’s a good running engine with no major issues, that he has seen come through their shop. And a course we know the 5.3 v8 are good engines, but have their little issue too.
Coincidently just today I dropped my truck off a MIT Driveline as I’m getting a new rear dif put in as the factory limited slip is plain wore out. I’ve got over 250K on my truck all original Powertrain. I mentioned the H3 to get their opinion. They said they have only seen a couple in the past 10-12 years come in their shop, so can’t give a fair observation. But said the only ones they have seen, have not come in for broken parts or repairs, only mods. They are not big fans of the IRS front suspension as they don’t articulate like a solid axle for off road and these guys are mostly Jeep guys. Another guy in the shop pointed out that he did not like that it was built on the mid size Colorado frame, and it’s just beefed up. But then another guy asked him if he’s ever seen or heard about a tweaked or bent Hummer frame? He said no, but he thought they should have made a specific frame for it.
In their limited knowledge of working on the H3, but overall opinion. They said they would buy a Jeep, because it’s what they know, and it’s got tons of aftermarket support. But the Hummer H3 is a nicer road driving and for its year a more comfortable ride vs a Jeep of those years, and with some standard features Jeep did not offer in those years. But don’t expect to off road or wheel it like you could a Jeep. But for light to mid off road, and for the pricing out there it’s probably a decent choice if looking for used off road capable vehicle, in that era and in the $13-18k price range.
BTW they were not aware with only adjusting the front torsion bars, that a 35 inch tire fits and does not rub on the H3. He said that was surprising and they did not know that big of a tire would fit stock with no mods or CV issues.