I'm not sure arrogance is the same as 20yrs ?? (I'll let Daz correct that figure) experience at the forefront of the landcruiser aftermarket here.
This has been a fix for busted diffs in stock standard 80s, 100s, 105s, and Hilux (Tacoma?), as well as a means of building competition tough diffs for the same for a long time over here. And no, we don't all beat on our rigs like the video posted earlier!
There's more than just Daz setting up diffs like this. There's been guys building competition diffs using machined solid spacers, increased preload, and deep contact patterns for a while with good results for competition rigs, not necessarily what you'd build for DD duties.
How many guys running Ultra 4 in USA are using Toyota diffs? I'd tip it is a relatively small number in mostly ftoys, or Tacoma, 4runners. All a lot lighter than an 80. And fitting a 4pinion locked carrier (ARB etc) goes part way to removing the failure mode.
If your building a purpose built buggy for ULTRA4, or desert racing in the USA, there's junkyards full of bigger, stronger corporate diff options available. In Aus, landcruiser is a FULL SIZE truck, we only have a very small handful of imported American F trucks, and even less of the Dodge/chrysler family, and wrecking yards full of landcruiser stuff.
There's different forces at play in tractor pulls (non existent in Aus) and drag racing (again, who drag races an 80?).
The handful of guys doing Aust4 racing (Ultra4 format) over here are using built up diffs, 14bolt, d60, d70 etc, but there's plenty of history of Toyota axles bring used and abused in other competition formats over here.
There's plenty of people who would struggle with the concept of 37 spline axles in an 80 for any tyre size, but hey, it's cool. Work with what you've got.
I don't think anyone it's selling this as the ONLY way to build a toyota diff for 37s. If I had thirds out to re-gear, I'd definitely, 100% go this route. I've wheeled my cruisers fairly hard (but with some mechanical sympathy) with 315s (35") on stock e-locked diffs with no issues.
I've busted a couple of CVs at times when I've let the red mist cloud my judgement
(eg, reverse front digs with steering on full lock. According to the collective wisdom, my stock hi-pinion front diff should have snapped like a carrot
