My truck won't start and I had trouble with my overdrive fuse kept blowing .I don't believe my altenater is bad could it be a fuse or on the wiring

 

Year? Model? Engine size?

These are all helpful in knowing whenever you post for help. Also, consider posting in the tech section dedicated to your year truck, as you may get more attention there instead of the general discussion here.

I'll move this thread over there once you let us know what year truck this is.

 

it's an2001 big engine 8 cylinder

 

So the only issue you are having is the fuse blowing? No dead battery? No other circuits/fuses affected?

 

Still need more info. Is it cranking but not firing or is it not cranking?
If not cranking always start by testing battery and battery connections. Many parts stores will do basic electrical tests for free but if you have access to a simple volt meter many tests can be done at home.
Welcome to the forum hope you can get problem sorted out.