If you got the grainier Vulcum then keep your eye on it. I tried some and within a year it started to deteriorate. I have used Trempro 635 from Vintage Trailer Supply which leaves a slick/shiney rubbery finish.
'01 2500hd ext. cab, 8.1 litre gas, 5 sp. Allison auto
3.73 rear end
Mag-Hytec rear diff cover
Amsoil Dual by-pass oil filtration system
Amsoil synthetics all around
265 watt AM Solar, Inc. system