D2 Top Roller - Need Help

I was clearing up an old fencerow, and the D2 was purring and doing a super job, including moving some pretty mammoth ledge rocks without breathing heavily.  Then I looked over and saw a roller sitting in the dirt.  It was the left top roller.  The support arm was fine - the roller just came off.  Back in the shed, I see three bolt holes in the support arm and a central hole for lube.  I put the roller in a vise and the three bolts came out ok, and the grease fitting.  It looks as though there are three smaller bolts inside that bolt to the horizontal support.  There is a bronze bushing inside the roller for the inner half.  I don't have a manual that cover the tracks.  Could anyone help me on what to take apart to put the roller back on?  It looks as though I should pull the bush out.  Somehow, there has to be an inner shell of some type that bolts to the support, then putting the roller on, I would bolt the outer 3 capscrews to hold it on.  But I don't see how to get things apart.  I am guessing the inner bolts came loose and let the entire top roller assembly slip off.  I don't see anywhere where things split and I should drive something apart.

The roller itself is in very rough shape with broken flanges.  As it is only a guide on top, I'm not concerned, but if anyone has a top roller for it in decent condition, I would like to buy it. 

Thanks in advance for the help.

The 3 bolts on the outside cap with the grease fitting need to be removed. Then the cap will come off and there will be 3 bolts holding a wear washer which holds the roller to the axle. The bols either came out or the washer failed. I have some extra top rollers and wear washers, bushings would need replaced ed. [attachment=62829]20210411_115849.jpg[/attachment]

Thanks so much for the diagram and description. Now that I know the end cap comes off, I can be a little more persuasive with the mallet. If you have a top roller in decent condition, could you PM me with the price, shipping to 13843, etc.? I would like to replace it if possible, even if I temporarily fix the current one with broken flanges.

pm sent