SR driveline: what's going bad?

[SHIFT_*grind*]

The car had been fine up until ~2 months ago, when we took it on a road trip to Baltimore, ~250mi each way. A couple times on the way back, I would get this wicked bad tranny whine: I'll be driving, and I'll put the clutch in, and the tranny starts whining/groaning really loud. I put it in neutral and it stops, and won't do it again when I put it back in gear. It's happened sporadically since the road trip, and I think it's getting more frequent.

What's up?

[WagDatto]

Tranny or could it be diff related? Check/replace your diff fluid, it might be whining, sending vibrations up the driveline to the tranny (which is partially in your car, maybe that's why you'd be hearing/feeling it there?).

Might as well do it anyway, fresh diff fluid is never a bad thing. You checked gear oil in the tranny lately, too? Might need to be topped off/replaced?

Just tossing out random "in front of your face" answers, since it almost always seems to be the easiest problem when you can't figure it out.

[SHIFT_*grind*]

Gear oil went in ~4 months ago, 2.5 qts I think. I hope it's not leaking...

Hadn't though about the diff.

[WagDatto]

It's probably not the diff, though it could be the subframe, bushings, etc.... I'd think that any kind of vibration in the driveline would transfer through the tranny/gear shift and be noticable to the touch and to hear.

[S14DB]

Input(pilot) Bushing most likely.

[waterboy]

pilot shaft bushing if its a high pitch sound