When I let out the clutch, I get a chatter around 1200 RPM. It does it about half the time. It last about 1/2 to 1 second. Sometimes it does it when I shift to second and it chatters around the same RPM range. Does not do it in 3, 4, and 5.
There is no loss of power, clutch feels like its grabbing. Just an audible chatter.
If it doesn't actually make the Jeep shake, could be a lifter or two sagging. Next time it happens, watch your oil pressure gauge to see if it does it at the lowest point of oil pressure. When the lifters do sag, they create more gap at the rocker than should be and will make a loud rattle sound.
It only takes a dozen or so bad launches to ruin a clutch. I could fry one in a mile if i wanted to. If its chattering it will just get worse over time and eventually just fail. Babying it the key to long clutch life. Hard high rpm launches will fry one quickly.
I'm not discounting the advise that it might be your clutch because that is certainly a possibility, however, I have the same exact symptoms and I just found the driver side motor mount is completely shot. The rubber is broken apart and the engine has about an inch to move around. New mount is on it's way. I'll post anupdate when it is installed this weekend. I am hopeful that that is the whole problem for me, but I could be in for some clutch service as well. We'll see.....