by KF5ZXT » Thu Sep 27, 2012 9:55 am
A strong box is essentially a doubler unit, goes in between the transfer case and transmission to add in an additional low (sometimes rarely a high) gear to increase crawl ratio (or overdrive). In it's general use, it allows you to 'go into low range twice' effectively compunding your low range gears. For example, the Borg Warner 1354/1356 transfer cases that come stock in early Explorers had a 2.48 low range. The Strong Box has a 2.48 low range. When both are engaged, you have a 6.15 low range.