truck wont start unless jumped, just clicks, but battery, starter, alt test good.

Hi, my truck requires a jump to start.  It just clicks a bunch when i turn the
key.  However, battery tests at 13.46v while off. same exact reading at the
solenoid.  alternator tested good at autozone.  took starter off and oreillys
tested it 4x, good each time.  i hooked starter to battery using jumper
cables, when i hit the positive clamp to the small bolt on the solenoid, it
made the flywheel stick out. then when i bypassed the solenoid with a
screwdriver, the flywheel stuck out and spins.  i did this on the connections
both before and after the solenoid. success both ways.  i also checked the
resistance on the relay, it's as it should be. even bought a new relay to
compare to. Why does my truck need a jump to start, when the battery is
good??  all my grounds are tight than i can tell. i found two grounds: one
from someplace behind engine and connected to firewall area. Second one
from battery to behind the bumper. theyre dirty but not corroded at all, and
they are tight.  and again, the solenoid has the same voltage reading as
the battery, so i konw the wiring between the two is good. i keep thinking
still that the solenoid is bad.... if it's clicking but wont start, then the ignition
wire is sending power to the solenoid, but it's not switching the solenoid on
the inside to pull directly from the battery cable....agree? thoughts? I'm no
mechanic... everything i said here is ALL i know.  i dont comprehend
anything else without spending 24 more hours on google and forums LOL.
THANK YOU IN ADVANCE!!!!