I have had some unfortunate events in past couple months. I have a 2000 F150 XL 4.2L V6. It had a 7" Fabtech suspension lift with 35" BFGoodRich Mud tires, MAC Cold Air Intake, Crane Cams Quick-Flow Power Spacer . My first set of 4:56 gears shattered. So I took it to Yarman Differential and got it rebuilt with new gears. 6 months later my differential failed again. So I gave up and bought a used stock 3.08 axle for CHEAP and picked up some Dunlop 275/70/16's (31.2" in diameter). The power sucked but it did ride alot smoother. Anyways yesterday I was driving down the blvd and made a right turn at a light and felt and heard a loud hard pop. So I drove it back home and took off the cover and found my stock spider gears are half GONE. So I decided to go look at my old axle. I opened it up and found that the ring and pinion and spider gears aren't broken at all. The large gear that bolts to the backside of the ring gear was eaten up. I'm considering replacing that gear and throwing the 4:56 axle back on. So my big question is... if I put the 4:56's on with the 31.2" tall tires will it be too much for the tires? I looked on the Gear Ratio to Tire Size chart and it shows that with that setup the RPM should roughly be 3213 at 65mph if I'm reading it all correctly. Should I do this or do you guys recommend taking the spider gears out of the 4:56 axle and putting them in the 3.08 . Please let me know what you guys think.