Everyone has given you great advice so far. Here's my $.02...
The first thing you should do is get the keys from the salesperson and then get them to leave you alone for a few minutes! Don't become attached to the truck. At this point you are not here to buy it, you are here to inspect it.
Don't start the truck just yet. You don't want to be conducting your inspection in a hot engine bay!
If you are looking at a higher mileage truck, check the bolts that attach the exhaust manifold to the block (especially the ones at the number six cylinder) and to the turbo. If the bolts are broken or they are missing altogether, this is very bad! Damage to these bolts will indicate that the truck was pushed extremely hard and subjected to excessively high exhaust gas temperatures. Also inspect the manifold, turbo housing, and down pipe for pitting caused by excessive heat.
While you are under the hood, loosen the intake tube from the front of the turbo and inspect the cold side of the unit. Check for obvious things such as nicks to the blades and then look for oil in the housing. Turbochargers are expensive pieces of equipment and oil in one means that the seals are failing and that a replacement is needed quite soon.
Check on and around the plastic covers on the various fuse and relay boxes on the sides of the engine bay. If there are small screw holes in these covers, odds are one of the previous owners had a performance chip on the truck. This may or may not be a bad thing, however, performance chips can lead to pre-mature wear on certain components such as the transmission and u-joints. Abused trucks are usually not reliable trucks! It is a good idea to assume that the previous owners were the kinds of people who thought they were mechanics, and that the world was their race track. We all know the type.
Next, crawl under the truck with a flash light and look for leaks. Focus on looking for dampness at hose or pipe fittings and where drive shafts some in or out of the various housings. A lot of dealers will de-grease a vehicle's engine prior to putting it out on the lot. This looks great, but it also helps them sell potential time-bombs to unsuspecting customers. If it has it's original trans, you can expect it to be leaking at the trans-cooler fittings... this is normal, just ignore it.
While you are under there, take a look at the suspension. Check for broken leafs and blown shocks. Inspect the bushings on the trailing links on the front of a 4x4 or the control arms of a 2x4. Check the sway-bars and end links for excessive play. Also inspect the track bar as this is a common issue on all second gen Dodge 4x4's.
Check all fluid levels, belts, hoses, and the manufacture dates on the batteries.
Walk around the truck and look for obvious things:
Tires: Matching tires, proper tire pressure, and tires of the correct load range. Are the primary tires or the spare dry-rotting, cupping, or otherwise worn un-evenly?
Body: Bring a magnet and check for bondo at the back corner of the cab and around the wheel wells. Check the bottoms of the doors and the tailgate for rust as well. Look for proper gaps between the various panels and doors.
Tailgate: Does the latch work properly and are the cables intact?
Box: Check the floor and front bulkhead for signs of abuse.
If the truck has passed every test so far, unlock it and open up all the doors checking the hinges and latches as you go. Also take this opportunity to inspect the seats, floor, seat belts, arm rests, cup holders and other parts of the interior for damage or excessive wear. Hop on up into the drives seat and start playing with the switches, buttons, and knobs. It is important that you check every system and then check every system with a few of the other systems running as well. Make sure you test everything from the dome lights down to the 12 volt sockets.
Assuming the truck is still passing the test, roll all the windows down, open the hood, and start it up. Listen for the sound of the pump priming the fuel system while the wait to start light is on. It shouldn't idle as smooth as a V-8 gasser... but it shouldn't be bucking like a wild bronco either. Power pulses should sound more or less even in rhythm and even in volume. Check for strange wobbles or noises coming from the accessories that are driven off the fan-belt.
With the truck idling, re-check all of the interior electronics and the climate controls. If you have a way of testing the fuel pressure, check the gauge now. If everything still checks out, let the truck idle while you grab a test drive plate from the salesperson.
When you head out onto the road, pay attention to what your dash is telling you. Those gauges are all there for a reason! Test the cruise control (it only works above 35 mph) and perform a series of braking maneuvers with your hands off of the steering wheel. Pulling, petal pulsation or wheel vibration during this test indicates a brake problem. Make sure the truck runs through all of it's gears properly and without hesitation or strange noises. When you step on the accelerator you should hear the turbo spool up. The truck should be responsive to even minor changes in throttle without surging or hesitation.
Listen for any noises that don't belong:
Whistling can indicate a door with an improper fit.
Clunking over bumps can mean a suspension problem.
Find an open and empty dirt parking lot and do a few slow, tight turns with the steering wheel at full lock listening for anything out of the ordinary. If it has it, test both 4x4H and 4x4L. Try to spin the tires a little and use the ruts you dug in the dirt to indicate that all of the wheels that should be turning are turning. Preform this test one more time just for fun and the re-check the fuel pressure.
If you have not done any stop-and-go driving yet, drive back to the dealer on a route that will hit a few traffic lights. The same goes for the highway if you have not taken a ride on it yet. Test the truck in both and look for proper handling and response in either situation. The test drive processes should take you at least 20-30 minutes.
If at any time the truck fails a test by your standards, walk away! There are other trucks out there so don't buy the first one you see.
Another option if you don't feel confident with your own inspection is to take it to a mechanic and have them look it over. Most guys will charge $30 to $40 to put the truck up on a hoist for inspection and then take it for a quick test drive. Even if you are confident with your own inspection, a second opinion never hurts.
If the truck passes all the tests and the price is right:
Congratulations! You have found the ultimate truck!
arty018:
