Doe on commercial jeep

Depends on who does your DOE. I've a 2003 Isuzu, and it's failed several times, never on anything traumatic, but things like worn suspension bushes, a worn track rod end, split CV boots and a corroded brake pipe(marginal), all of which was done without too much pain. It's also had rear shocks replaced as it was clear they would fail, a new back box, and a few other things like that which would have been fails if it had been put in without replacing them, but the bottom line is that it all depends on the tester, and the quality of the test,

The tester I have used for a long time is realistic. They don't get upset about a bit of surface rust, or even a few creases in panels, but they will fail things that are out of the tolerance of the test, which is what it's all about.

The DOE is not different than the NCT in terms of what it does, the difference is that because of the size and types of vehicle involved, some of the equipment used for the NCT would not be suitable for testing a commercial vehicle, mainly because of the size, length and weight, so a different facility is needed.

A new DOE is no more than an indication that on the day it was presented for test, it met the basic requirements of the test, including things like emissions, brake efficiency, wheel alignment and similar things. There's no indication of the state of things like gearbox, axles, transmission, and clutch, all of which may have taken a hammering, especially if there's a tow bar on the vehicle and it's been towing heavy trailers on a regular basis. The only way to find that out will be to test drive it, and see what noises it makes, how well it changes gear, where on the travel the clutch pedal goes, and a general feel for the overall condition. If you can test drive it when the oil and gearbox and axles are cold, and warm them up during the test drive, that may also give some clues. Most 4 x 4's are not massively powerful engines as such, so persuading the clutch to slip if it's worn may not be easy, flooring it at low revs in a high gear might persuade it to slip, and if you are experienced at gently dabbing the clutch while pulling power, that might also show up any weakness, but be careful, you don't want to risk it failing while you are test driving, the owner might not be too happy about that!

Overall under bonnet condition, general engine noises, again, especially if started from cold, may also be a clue, and will show up if any of the pre heaters are suspect.

How well the doors fit, the wear on seats and pedal rubbers will also be a clue, you should be able to tell if it's been tarted up to sell, or if it's been regularly maintained and cared for by the appearance of the engine compartment.

Hope that helps