The Spicer 18 originally came equipped with a drum-style parking brake on the rear output. The trouble is, over years the driveshaft yoke studs can flex and wallow the bores of the cast iron into which they’re pressed. When you try to take the rear shaft out for a field fix, the studs often spin inside the brake drum backing plate and the shaft can’t be removed. You can either tack-weld the studs or replace them with hex-head bolts that won’t spin as the nuts are removed. Also, in this photo you can barely see the Advance Adapters chain clutch linkage. It’s way better off-road than the factory cable- or rod-type linkage and still works when the chassis is all flexed up.