sliping out of 4H to neutral- need to use today

[chevyguygoneford]

went to put my '05 f350 powerstroke auto trans into 4H yesterday and it kept sliping out to neutral. i could hold it just rite and get it to stay in 4 high but i cant drive to the job site holding the shifter. always owned chevys till now and have never delt with this problem before any helps apprciated. sorry new to powerstrokes so i dont have mutch contributing imput to this site yet.

[Pilgrim]

Can you use 2H? It sounds like you've got a manual transfer case shifter, correct? If I were you, I'd go ahead and get under it and investigate.