The front axle is a traditional axle like you'd find under the front of any 4WD truck, it's got a cover (not a pig/chunk like the rear). The rear axle is designed like a Chrysler 8.75" / Ford 9", with a drop out Third Member/Pig/Chunk. IIRC the Front Axle is an 8" axle (ring size) and the Rear Axle is an 8.5" (ring size)

Here's a picture of the Front Axle in a 4WD D50.



I'll set both axles aside for you, recian. The front axle is the whole differential (minus the CV Axles / Half Shafts), the rear axle is complete (minus one brake drum).