Orig tires doesn't matter so much as correct size. Pressures can make for increased wear and problems with 4X4 and any traction controls/antilock brakes even if messed up.
If max on tire is rated for 44psi and you have to pick a # I'd probably pick 35psi all around first and if they looked and handled well leave it at that year round and keep checking - good thing to do anyway.
This type vehicle could have come with optional HD things and had tires that suggested more than 44psi - I just don't know.
Pick something over 32 anyway and if the orig sticker had different pressure for front vs rear consider that and make the calculated guess accordingly.
If you note funny tire wear come back for suggestions. Always best to rotate tires regularly to allow them all to wear at the same rate. Good luck,
T
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Tom Greenleaf - MetroWest, Boston