Bought a brand new Wagner brand brass float from Dan's Classics in Portland several years back. I think they were $10-15 bucks. I was going to buy from NAPA but it would have been a special order. Dan's had them in stock so I bought from him. I didn't trust soldering the old float but sounds like it has worked for some.

"The Operation of GMC trucks is normally smooth and steady, with no loud rattling, knocking or unusual noises. A good driver will quickly become accustomed to driving a GMC truck and will get the feel of his vehicle regardless of his engineering knowledge."-TM10-1563