I tried inquring about this at the one Usenet Isuzu
newsgroup but am not getting any feedback.

Friends of mine have a 2000, 3.5 Liter, 4-wheel drive,
automatic transmission, Isuzu Trooper. While driving it up a
large hill (really, the foothills of a serious Western
mountain range), the car stopped running. I don't have the
details on this, but subsequently, they had it towed to a
nearby mechanic who works on Isuzus and he said it had
thrown a rod. The car is currently sitting in the lot of
another friend who has some background in auto/truck
mechanics but has not yet had a chance to look at it. I am
going to look under the hood sometime in the near future and
try to verify the thrown rod and destruction of the engine.
The owner said he was a bit remiss about oil changes but did
have them done every 10k miles or one year at least. Some
questions:

-- From my googling, a thrown rod can be very obvious: A
steel rod pushes through the crankcase or engine block. Can
it also be not so obvious? E.g. suppose the rod has
disconnected from the piston head, and it's just banging
around inside the cylinder. The latter scenario presumes the
vehicle was stopped quickly. What else can I look for? I am
not sure I will be able to try to start it up yet.

-- I have been making online inquiries of salvage yards
about (1) used cylinder blocks; (2) used, entire engines.
Dumb question but I'm not quite clear on this point: Does it
matter whether the used engine was attached to a 2WD Isuzu
Trooper? It seems both 2WD and 4WD Troopers, of the same 3.5
Liter engine displacement, are available.

-- I am getting quotes back in the $3k-$4k range but from
yards many states away. Shipping seems pretty reasonable and
common. Has anyone purchased an engine or cylinder block
from several states away? What kind of assurances can I get
about the condition of the engine? One seller so far has
said he has a CarFax report verifying the engine has only
seen 32k miles. I plan to check locally, too.

-- Evidently going up hills in too high a gear can throw a
rod. The high gear translates to low revs but high torque,
stressing, from what I understand, the piston rod,
crankshaft, and associated bearings. Can anyone elaborate
further on this? It might help me to identify whether a rod
was actually thrown.

-- I understand installing a new engine is around a day's
work, maybe less. This so? I am going to try to get a quote
for the labor from my favorite import shop in mind but will
also inquire at the nearest Isuzu dealer. Anything in
particular I should ask them other than: "How much to remove
an old engine and install a second-hand one?"

The owners of this car do an astonishing amount of volunteer
work in animal rescue. They are down to one truck (while
normally having two). Given the circumstances, your
assistance is especially appreciated.

(Honda note: Isuzu has done some business on the trucking
side with Honda.)