well, looks like i'm wrong. got this off 4crawler.com....
Above are photos of the various Toyota 8" 3rd member housings. All the housings are interchaneable in that the mounting studs and axle splines are identical. The 4 cyl differential internals are different than the V6 and High Pinion, so that lockers and limited slips are different. The 4 cyl ring and pinion gears are somewhat smaller overall than the V6 parts, i.e. the ring gear is thinner and the pinion gear and bearing are less substantial. The 4- and 6-cyl housings can be distinguised by the number and style of reinforcing ribs present.
The 4- and 6-cyl housings may be used in rear or front applications. The pinion (or companion) flange nut takes a 30mm socket.
The High Pinion diff uses reverse cut gears and is best suited for front solid axle applications. While it shares internals with the V6 diff, the gears are unique to the High Pinion due to the reverse cut, which puts the gears on the drive side of the teeth in the front axle. High pinion diffs are commonly found in 1990-1997 FJ-80 and FJZ-80 model Landcruisers that had the solid front axles. Ironically, the high pinion diff was not designed for the added ground clearance, but rather so that the steering tie rod on the FJ-80 could be run *below* the front driveshaft to keep the vehicle low!
