Not one of the three that hold it to the block but one of the long ones that is used to hold the starter together. Faces the front of the truck. I tried to screw it back in but it wont go. Any reason to worry?

 

Is it stripped? Maybe it's just misaligned. I'd pull the starter and try to screw it back in. I'd be worried about water splashing in there since it's no longer sealed.

 

Not really that hard to pull. Make sure batterys are disconnected.
Small hand wrench with cheater gets them broke loose. Never can get them loose with socket, extension, u-joint, ect.

 

I say pull the starter while your there check the contacts.

 

once pulled put some of the "blue" loctite on there. It won't lock the bolts in but "seal" them and prevent backout. I've used this stuff on starter bolts 10 different ways and it works very well. I use it on other bolts that tend to come loose also.

 

Must be one of those long ones where you need 5/16" or 8mm socket.
Locktite is a good idea.

 

As was said...might be a good time to replace the starter contacts with upgraded ones:

http://www.fostertruck.com/contacts_install.htm

 

Starter Contacts are fine, did them not long ago. Just worried about the bolt. Thanks for the info.