I tried to start my truck 2 days ago and my starter would not disengage forcing me to disconnect both batteries to shut it down.after reconnecting them i tried again same thing every time i have checked every fuse i can see nothing seems to be blown.

 

sounds like your starter solinoid or ign. switch is stuck

 

My money's on the selenoid. I've had it happen before on other vehicles I've owned.

 

By the way, welcome to the site! You'll like it here. A lot of information and experience here!

 

starter solonoid, happened frequently at the dealer's

 

wondering if i need to replace starter or if it is a simple thing like a relay or a fuse that needs to be replaced

 

You should have a starter relay on the passenger side wheel well. If the problem is in the selenoid, replacing the starter will do no good. On these trucks the selenoid is seperate from the starter.

 

Was it cranking really slow, like the batteries were weak?
I have a truck that sits for long periods and the old batts die down. I know when I crank it if it doesn't start up, I need to jump out and unhook the batteries cause it'll keep cranking. All due to low batts. Full charge, no problem.

 

2nd that the older Macks will do the sme thing with low batteries, charge the batteries first and then try it.

Mike