Alas, I have figured it out. It was the shift range fork pads. One had worn through and broken off and the range fork was clanging against the clutch sleeve. Pretty easy fix, just had to tear things apart to find it.
Yeah, the chain is sort of where my head was. I plan to open it up Saturday to take a look. If it is the chain, I will replace it. If it is more, I will start shopping used/rebuilt TCs.
Thanks for the feedback.
That is actually what I thought, so I changed it before posting here. It was about 1/2 Qt low when I drained it, but it is now full. No change, however, in the rattling.
Bottom line, I am just trying to figure out next steps. Right now, I am assuming the chain is loose and plan to open it...
Doesn't matter. Shortly after starting - while still at idle - the rattling starts...and that is true whether the TC is in 4H, 2H, N or 4L. I can shift the TC between 4H, 2H, N or 4L as well, but doing so doesn't impact the rattle. Same for the Transmission. Either in N or in Gear (always...