Long story short (ha!) decided to regear to 4.56 for the bigger tires. Thought, well thats straight forward. D60 front, 10.5 rear, 3.73 stock gears. Front will use a "thick gear" so no carrier change is needed. Then there's the rear..... let the fun begin.
WHAT THE F#CK did Ford do with the early job1 axles?? I stopped by my shop today (who are beyond-capable of doing gear installs) to check on the progress to find the rear diff has been apart all day and they're trying to figure out what the hell has been thrown together from the factory.
BESIDES the fact that the preload was off and things weren't that tight in there (from the factory, keep in mind), it turns out, there were some changes in the pinion bearings on the 08 axles. The install-kit and gears are for an 08 ford (duh). Well what came OUT of the truck was NOT what was "supposed" to be in there according to numerous sources like Randys Ring & Pinion, and FORD themselves. Not only that... half of the parts in there had NO part numbers on them. Just blank (parts that SHOULD have been marked)! Its all timken stuff, but nothing was marked as it should have been according to everyones manuals and specs, so it was next to impossible to figure out whats been thrown together in there.
I don't have much more in the way of info tonight, but should have pics and more info tomorrow. Just curious if anyone has heard of anything like this before. Right now, it appears that the axle is a hybrid of parts that don't match 07-down or 08-up entirely, and has a big white "70" (Dana-70??) upside down in something resembling chalk (but doesn't wipe off), on the rear of the drivers side axle tube.
Truck has a build date of 4/1/07, SRW, F350 diesel, cc/sb.