Trevor? previously posted:
"It's a custom truck so who knows how it's configured, but some other 3 axle conversions are intended to drive from one axle on the road."
If you read the details, its configured with two rear driveshafts - one from the centered D20 output, and then modified with an offset D18 output as well. The centered D20 driveshaft passes over the the first rear axle and goes to the second axle. The offset D18 drives the first rear axle same as it does on mine - meaning the rear axles have pumpkins that are not 'inline'. The front axle is also driven through the offset D18/20 t-case - all axles are D44 (although I think one of the rear ones is in a ford housing). Definitely a one-off build - its been featured a few times over the years in mags - mostly back in the 70-80s I believe. Ed Holbrook was a early founding members of Jolly Jeepers and his long leaf springs were the standard go to for flat fender jeeps until very recently. I think Rocky Road or somebody like that bought them out, but they seem to have ended production... A quick google will bring you lots of info...its unclear if the current seller really knows much about it. I think it sold on ewillys only a few years ago.
some additional info:
http://www.jollyjeepers.org/members/pages/eholbrook.htm