I've been searching for a used "Gear Vendors" under/over drive unit all over the nation and the ones I found were from $500-&1,500 and they need to be rebuilt. Then, without much hope I called one of the last remaining wrecking yards in my area. Long story short they had a t400, GV, parking brake, still all connected out of a motorhome. I bought the whole package for $400 - and on new years eve none the less! At least 2020 ended on a good buy!