The ’63-’70 Wagoneers came with the less desirable and leaky closed-knuckle Dana 27 front axle. The later models have the stronger open-knuckle Dana 44. The 44 can be swapped into the older models with little difficulty. Watch out though, some later wagoneers have the differential on the driver side. There are also a few IFS Wagoneers out there with a Dana 44 centersection.