Have you tried to take your part to a HDT repair shop to see if they have a match? Keep in mind this is not a custom-made part especially for Winnebago. In fact, when you look at the parts listing for your specific model, it usually shows the mfgr and their part #.
2000 Winnebago Ultimate Freedom USQ40JD,
ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG 11B5MX,Infantry retired;Good Sam Life member,FMCA." My fellow Americans, ask not what your country can do for you, ask what you can do for your country. John F. Kennedy