Body and rust are obvious items,
1) Check for any obvious fluid leaks,
especially the engine valley, tranny weep hole area, and around the turbo and
2) Check coolant with strips and find out the record of any
changes or water pump replacement based on mileage.
3) If possible, do
compression check, and Cylinder contribution test.
4) Inspect turbo inlet
side vanes, should be straight and not dusted or jagged. Try to move the shaft
in and out and up and down. Any real noticeable movement by hand is bad. Open
and inspect air cleaner assembly for an idea of how it was maintained.
If possible, have fuel pressure tested at engine to check pump.
all intake /intercooler boots for residue or leaks and correct before trying to
determine engine condition.
7) Look at oil pan for notorious rusting,
make sure not beyond repaint type repair.
8) Know whether you’re getting
forged or PMRs. 99-mid 01 = forged, anything later is possible or for sure PMR.
Not an issue until you exceed 400HP.
Transmission, driveline and 4×4
1) Look for any obvious leaks.
2) With the system in
2wd, grasp and rotate both front drive axles and ensure they rotate freely. Go
to the hubs, ESOF and manual should rotate from lock/auto to free with no
3) Grab rear driveshaft and push up and down along it’s length
checking for worn u-joints or bearings.
4) Check front and rear
differential levels. (An indicator of maintenance) Level should be at or w/in
1/2 inch of check plug.
If you have never owned
a 7.3 PSD, try to get a 7.3 owner to test drive it. I did this with a friend who
bought his new. Invaluable evalation because you have no idea. A stock PSD may
feel like a slug to the gasser uninitiated but it can pull a house off of it’s
foundation. So here we go.
A. Drive more than one PSD truck that you are
considering. Whether Auto or Stick, it will give you an idea of the overall
condition of the one you want to buy. Cost = 0. Learning curve = super high.
Dealers have a ready supply.
Turn key and watch
wait to start light. The colder it is the longer it will take but should take no
longer than 15-20 seconds on even cold days. Start engine. Should crank readily
and turn the tach while cranking (although mine does not). Should start within
2-5 seconds of cranking. The colder it is the longer it will take but if longer
than 5 seconds there may be a problem. Even in colder weather. If it does not
not start easily on the second try, suspect problems, possibly in the glow plugs
or GP relays. If it does not crank readily, or seems to drag, suspect batteries
first, starter next, then cables.
operational items. Don’t be rushed. This is a major investment and you want to
get it right. Even small items like the cruise will set you back.
tranny: will feel like it takes the throttle to get moving with a stocker. The
higher the mileage, the worse this will be. The shift should be smooth but
slippy with a stocker. Long to engage. Convertor lockup will be almost
imperceptable, but there. Will lock up at about 45 to 60m depending on throttle
in OD. Should drop out of OD with input to brake or reduction of
2) Standard: give input
3) Ride: if it is bouncing down the
road, you can look to having some problems to take care of. These can be tire
balance. Tires, or some unexplained seemingly incurable symptom that you may
have to live with which is unacceptable and not common, but does happen. Some
say it is an out of balance driveline but there is no universal cure.
Exhaust drone. Only happens with aftermarket exhaust due to what I believe is
harmonics resonating in the thinner walled aftermarket systems. Not a big
solution at present but not a performance issue.
5) Performance. There is
no hesitation in the PSD 7.3 when all is in working order. Any hesitation is an
indicator of a problem. By design, if all is in order, at throttle tip in, it
simply responds. No excuse such as mileage considerations. This = repair bill.