454cid
Sooper Pooper
Yeah, there's one part on the rear driveshaft (photographed in this post) that has the blue Teflon coating. I'm going to use Dawn and a nylon brush to clean it, but definitely not going to use anything harsh for fear of removing the coating.
On the other hand, the splines on the front yoke don't have the coating.
That looks different than what I was thinking, but I think you have a Dana/Spicer driveshaft. I was thinking of a black coating.
I think this spline shaft might have it https://www.gmt400.com/threads/xxxparagonxxx’s-1999-chevrolet-k2500-crew-cab.56388/post-1282866