The Nissan Path

im at 183,400 miles truck ran perfect until today. got home from work, wanted to go fishing turned the key and wont turn. checked radiator and oil looks clean as can be, will check tranny fluid and come back with response.

my question is it too late that I never did the by pass? or get a new radiator? or hopefully this isn't the issue at all

I had an issues similar to this the other day. Try wiggling your gearshift and see if the engine will turn over...

I think just because your truck won't start that it is jumping the gun to automatically start assuming cross-contamination is the cause. You don't mention if it cranks and doesn't start or if it doesn't crank at all. If it's the latter, I would start by checking the battery and the battery cable connections. If course, it's quick and easy to pull the dipstick and check for cross-contamination, but most cross-contamination incidents don't result in no-starts; vibration at highway speeds, transmission codes triggering and/or slippage during shifting are the usual symptoms. A bad PNP switch can also cause a no start, but usually triggers a code when it's bad.