Welcome to iRV2.
Sorry you're here with problems.
If it's a straight section of hose , NAPA or Auto Zone should be able to supply fuel rated hose the size you need . If it's a formed hose you may have to contact Freightliner.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.