The single Cardan/Spicer universal joint is also known as
the cross or four-point joint. These two names aptly describe
the single Cardan, since the joint itself forms a
cross, with four machined trunnions or points equally
spaced around the center of the axis. Needle bearings
used to abate friction and provide smoother operation are
set in bearing cups. The trunnions of the cross fit into the
cup assemblies and the cup assemblies fit snugly into
the driving and driven universal joint yokes. U-joint
movement takes place between the trunnions, needle
bearings, and bearing cups. There should be no movement
between the bearing cup and its bore in the universal
joint yoke. The bearings are normally held in place
by snap rings that drop into grooves in the yoke's bearing
bores. The bearing caps allow free movement between
the trunnion and yoke. The needle bearing caps may also
be pressed into the yokes, bolted to the yokes, or held in
place with U-bolts or metal straps.