TR2/3/3A steering box question

Hello people.. OK, why is the lower mounting hole in the mounting bracket (trunnion bracket) enlarged? ie upper bolt hole is 5/16, lower is 9/16. Reading between the lines of other posts, it may be adjustment slop for the steering column alignment. But I may have lost a special bolt or sleeve. It's been quite a while since I disassembled the front end.
While on the steering box subject, how would I know if the box needs rebuilding. Is there something I can pull or shake to tell me if there is too much backlash in the gear..or whatever goes bad? It's a split column and there doesn't seem to be any play or lag between turning the upper half of the column and movement of the drop arm. Or..should it be restored routinely every 60 years. I'd rather not but I would. Thanks

Yes, the oversize hole is to allow for vertical alignment of the steering column. The clamp where the box mounts in the bracket also allows for horizontal alignment. It needs to be a straight line all the way to the steering wheel, so get it all lined up (body in place of course) before tightening the bolts.

My opinion, if you don't know it was serviced recently (or even if it was and you have doubts about the work); replace the bushing and seal. The clearance in that bushing should be less than you can detect by hand (at least less than I can detect). And, again IMO, wear in that bushing is the primary cause of heavy steering. It won't bind when the box isn't working against the resistance of the front wheels on the pavement, but when actually trying to steer the car, even a tiny bit of wear will allow the rocker shaft to tilt, which in turn causes the peg to bind in the groove. You get binding even when the adjustments are loose enough to cause significant slop in the steering.

Seals get old and hard even sitting in a barn; and a leak there is rather annoying. The box doesn't hold much, so any leak at all means you have to add oil all the time. (Unlike the engine, which mostly leaks only when running, the steering box will leak constantly if it leaks at all.)

While you're at it, inspect the peg for wear. It's cheap and reasonably easy to replace once the box is apart; much, much harder to service later. If you can see wear marks, I'd go ahead and replace it now, while you can. Be careful when pressing the new peg into place though. It has to go in straight or it will ruin the hole.

Look the bearings over too. The balls can be replaced individually (if you can't find the ball and cage assembly). If any of them show rough spots or visible damage (even just a 'matte' appearance), I would change them all.