Truck wont crank!!!
 

I have a 1997 Chevy K2500 with the 6.5TD. 2 nights ago I was leaving work and I tried to start my truck. It cranked 2 or 3 times but it was 8 degrees outside so it was slow. I let my glow plugs cycle a couple times and tried again and my truck wouldnt crank. The starter rod shoots out but doesnt spin. I had it tested at Advance Auto Parts and the guy tested it 5 times and every time it tested fine. I tested my ignition wire going to the starter and it tested at 11.89 volts with the ignition in start. I turned the motor from the flywheel with a small flat head screwdriver and it turned just fine. I put the starter back up and it did the same thing. The rod shoots out but it doesnt spin. So I bought a starter relay to see if that was the problem, that didnt work. Does anyone know what could be causing this. PLEASE HELP!!!!!

11.89 volts is a low battery voltage it should read 12.06 to 13.00 + volts. Try jumping it and find out why the voltage is low at the starter check battery's + alternator check the dumb stuff like clean battery connections, charging wire from alternator is clean and proper electrolyte level in battery.

just because you had the start test does not mean it good i have seen it many times they can test them say there good but it don't have the load on it like these motors do