Factory welds these toothed rings now, as do rebuilders.

Lifttrainer,
cutting the steer sensor rail is old news and would apply to early model trucks from 2004-2006. But some low use trucks are out there with old software.They would still have longer "flags" or sensor bars.
Like I said, factory messed with this many many times. Early system had steering hit stops hard, then current was cut back to the steer motor. This took out steer rings and blew steer amps. Newer Style has shorter "flag" with software that uses the prox to see Flag ends. Now, as the prox sees the end of the flag as you turn, it counts degrees of movement and cuts off steering before the drive unit hits the stops hard. Even with this new system, the first time you steer hard to each end, it hits the stops. After that it learns, then wont hit either end as you turn. As for axial play in radial rings, the factory will not warrantee a drive unit unless it has 120. thou play. But yes, replace them if they hit 90 thou. You need a dial guage, jack up truck, set guage then drop truck to floor. Driving with the door off will show the drive motor swing back and forth with clunking sound on plugging. The fixed position steer motor takes a beating here! Some fresh factory rebuilds have 60 thou right out of the box. Every 7400 drive I've taken apart has wear on the square shoulders where the rings sit. That usually means the unit is shot, but we put new rings in and let it go. Rebuilders do the same thing because i've taken one apart and realized the fresh rebuild had wear in same places.
Advice to anyone working or maintaining 7400's.grease radial rings every 100 hrs. There are NO seals to hold grease or protect steel **** Grease simply falls out the bottom. You can actually see the **** from the bottom side if no grease is present. Once that layer of protection is gone, very rapid radial ring wear occurs. THEN, you could lose steering, get GD codes, loose the steer motor due to side stress, and lose the steer amp from overcurrent while it's trying to turn a seized drive unit. 3000 hrs is as far as you get before needing radial rings....but greasing more frequently increases life. Just remember, most electrical steer error codes are caused my mechanical wear.