I welded mine a little differently than everybody else does. Rather than welding the gears solidly together I welded the space inbetween the gear teeth. I welded four teeth on each side gear, and 2 teeth on each axle gear. They are welded so that the welded teeth contacte eachother when the gears turn. Leaving the gears loose you rely on the gear teeth rather than the welds to transfer power, reducing the stress and fatigue on the welds. You also allow a very small amount of slip (1/8 turn) which helps prevent breaking axles. A friend of mine did his Jeep XJ the same way, and he's been driving it daily and beating it in the bush (and I do mean beating) for three years now with no issues.