Am I missing an end cap here?
Have had intermittent speedometer issues lately and just having a look now.

 

End cap is gone get a hole saw cut a piece of tin glue on with Right Stuff silicone

 

sounds like a plan, thanks Jim

 

Speedo gear drive part 2
Well after making a seemingly suitable repair I found the end cap and small washer sitting right on the transmission cross member.
Does this need a O-ring in the grove?
Thanks.

 

Boy you sure lucked out finding the parts on the crossmember!! No o-ring that I'm aware of. I'd clean it up real good & put a little adhesive silicone around it. You might want to use a small center punch & go around the opening to tighten it up a bit before you press that end cap back in.