1. Did ford ever build posi's with 4-sping center springs?
2. Is it normal to have to remove material from the inside of of the housings? I would think not as you would have to be very carefull to remove the right amount due to carrier expansion being different than the gears. I did not have to do this with my posi unit.
3. I know reusing the pinion shim is OK as long as Ford gears were used, but simply reusing the pinion shims would not be OK?
4. If the carrier is not a ford unit then you definetly would be unlikely to get a good gear tooth pattern by simply reusing the shims?
5. It looked there was allot of clutch material and clutches seemed smooth. If friction modifier was not used would this be a problem?
1. I've never seen a Ford Trac-lok with anything other than the typical S spring.
2. Not normal.
3. MOST of the time, I've seen the same pinion shims used when replacing ring gear and pinion IF they are Ford gears. Ford seemed to have had good QC on pinion depth settings across the board.
4. I've NEVER put a carrier in that used the exact same shim pack. It may be close but usually requires some shuffling of the shims. Whether the bearings are new or used plays a part in this as well. A lot depends on how close to perfection you are settling for on the gear mesh pattern.
5. Stack height is more of a concern with the clutches than the clutch surface. The clutches are designed to slip in normal use. More slippage equals more wear which results in less stack height.