Here’s one drawback to the 8.4 axle. The factory 2WD V-6 Tacoma third member won’t accept low (numerically high) gearsets like the 4.88:1 gears we wanted to run. The stock drop-in third member is geared to a pathetic 3.15:1 and is useless to us since it is machined differently for the stock ring gear. Fortunately, any 8.4-inch third member will fit this axle, so you could hypothetically get a used four-cylinder 4WD Tacoma rear third member with a 4.10:1 ratio right from a junkyard. Unfortunately, the Toyota electric locker won’t fit the 8.4 axlehousing. Here you can see the large bearing caps on the sides of the 8.4-inch differential. For sale.