Our Tekonsha converters like the # 119250KIT are a great option. This has a higher amperage rating than most modules and we've found it to be very reliable as well. view full answer...
We do have the B&W Tow & Stow 3-Ball Mount # BWTS30049B for a 3" hitch. This has a 1-7/8", 2" and 2-5/16" ball and is rated for up to 21,000 lbs. That one is the 7" rise/drop, we also have the # BWTS30048B for a 4" drop/rise view full answer...
The 2008 GMC W4500 would not have a brake controller wiring port as it wasn't initially intended for towing. Since this is a box truck application you'd have to hardwire in a controller after installing a 4-way harness as a base for that.
For a 4-way to start you'd need a universal kit part and then convert it to a 7-way with the part # ETBC7. view full answer...