F250 gear problem
 

My 1987 f250 won't shift out of first gear... its an atomatic transmission and goes till about 25 before sounding hot. what exactly should i do to try and solve the problem???

I believe the trans in question is a C 6.
You might check the detent (downshift) rod coming off the carb going to the trans.
Also the govenor assy on the tailshaft is either stuck or badly worn.
The gov influences shifting. With a transfer case behind the trans , if its 4 WD can be a little more work to get to the govenor.

is it a simple fix or something worth replaceing

You can't just go replacing things until you are sure of what isn't working.
The downshift rod is a simple thing to check.