F250 Diesel Starter Removal

I think I have to replace the starter on a '86 6.9L F250 diesel.
thought it would be easy.Removed 2 srews " in front", ?1 bigger bolt in the back.Still doesn come off.My books dont show anything.
there might be a 3rd bolt in front but higher up.I feel something but cant see,akso probably no room to use a wrench.
Any help appreciated