1994 F-150 T-Case

[abregar]

My 94 F150 currently has the push button 4WD. It only has high range, for some reason it will not go into low range. For this reason I would like to swap out that case and put in one with the manual selector. My question is which case would go into the truck with the minimal amount of work? And is this a strong case for mild off road use? I don't know Ford t-cases.