Shudder While Engaging 1st Gear

[CriticalMass]

I've been driving the car off and on for over a decade, so this is definitely an emergent issue and not just a matter of getting used to the car. It was in the care of a third party for the last two years while I was overseas and the issue developed during that time. I've only driven it once with the issue to get it from their place to mine when I took possession of it again after returning home. It then went up on blocks for winter storage. I'm in the process of trying to get it ready for summer driving now.

I recall starting from a stop in 2nd gear and having the same symptoms and particularly remember getting shudder in reverse as well when backing it up my driveway into the garage, so it's not specific to a particular gear. I didn't notice any change with heat (over the duration of one drive) and can't recall deliberately slipping the clutch, so I don't know about that. It did not have any adverse symptoms at speed while changing gears, and again, I couldn't get any RPM spike in 4th while standing on the throttle.

Regardless, I figure it is most probably a clutch issue as well. Just wanted to make sure I wasn't overlooking something stupid before I crack into this thing.

So on that note, any good references for the process? Can I do it from below the car, or do I need to remove the transmission tunnel? Should I take the opportunity to refurbish the transmission while I'm at it even though it's operating normally, or not worth it?

Thanks for the help, guys.