This truck has a timing chain, not a belt. The chain will last longer than a belt and should not be replaced until it fails.
A 1997 Ford Explorer , 5.0 litre / 302 cubic inch V8 engine has ( 1 ) timing CHAIN
There is not any set time as they very seldom go bad.
the turn signal flasher and hazzards on these models are not seperate components. but the function is handled by a timer within the switch. when turn signal is on you should hear it click. considering all bulbs are ok ! if it is bad, the hazzard switch needs replaced.
The switch isn't repairable and should be replaced if bad. It's located on the bar where the brake pedal is attached.
there should be a button behind the glove box area..you may have been hit by another vehicle when your vehicle was hit the impact shuts off the fuel pump for safety fire hazzards
The radio could have a short in a wire that is being bounced and causing it to turn off. It also could be the radio is going out and should be replaced.
if you already replaced everything under the hood, u may as well keep going. you have already spent money and should now have as new engine
If computer hardware in waranty we will replaced that thing or should be changed to another
Impossible to say. If it was totally rebuilt and done correctly, with proper service it should last as long as a new one. If it is a used transmission, who knows.
The battery is weak and should be replaced, with a charged one or new one.
Overdrive is controlled by the shift solenoid, and vacuum modulator. the kick down you refer to is not overdrive but passing gear and should also be controlled by vacuum.