4 Wheel Drive/SUVs: weird Jeep noise when starting and shutting down the engine, jeep death wobble, jeep exhaust

Question
I have a 1996 cherokee sport 4wd. automatic.  I am the sole owner, and have all records.  Yesterday, I noticed a weird noise. when I start the jeep there is a weird, slight (almost imperceptable) metallic sound preceding a hesitation or hitch that is so slight if I wasn't paying attention I wouldn't notice it. the sound is almost clear. I have never heard such a noise.  There is also a small similar noise when I turn OFF the Jeep.  Mileage is 48562 give or take a mile.  I do regular maintenance, recently had the tranny flush, new tires, am never late or oil or fluid changes, etc.  I am at a loss as to the origination of the sound.  Nothing appears to be loose or hanging wrong underneath the jeep (exhaust pipe, etc).

this noise is not to be confused with the noises that all jeeps seem to make when climbing a hil, etc.  I believe it has something to do with starting and turning off engine, so I am looking for suggestions.

I have a good mechanic, but I like to know kind of what is going on before I go to him.  I hate sounding so girly and complaining of a noise.

the jeep has new tires which seem to have gotten ride of the jeep death wobble (firestone destination le, new ball joints, heaviershock didn't hurt either).

I was rear ended in march, but that big metal bumper staved off damages save replacing the original bumper with a new one. then in june, a deer literally jumped on my windshield, but again, no big damage save a new windshiel and a couple of scratches.

so that is the story of my jeep...if you can direct me as to where I should be looking for the noise, that would be most appreciated

Answer
Carla,

This sounds like it may be the fan belt, idler pulley on the belt, or another belt driven component, such as the alternator, or air conditioning pump.  

If you can't locate the sound yourself, I would take it to your mechanic, and see if he can locate it.  Most mechanics have an automotive stethascope that they use to isolate sounds like you are describing.

With your mileage, I doubt if the problem is anything serious.

Don't worry about sounding foolish, as it's better to take care of a minor problem, before it becomes major.

Carl