Clutch material gets a little softer, thus more "grabby" when it's hot.
Did your last clutch have the same problem - chatter?
Did you put on the bigger tires at the same time you did the clutch?
Did you re-gear at the same time you did the clutch?
Are you sure Gremlins didn't sneak in and change things during the night?
No? Then why would it suddenly cause chatter now?
Larger tires or wrong gearing just means you have to slip it a little longer. But it still should not "grab" or chatter.
It's usually an easy fix - about 80% of the time - a problem you introduced when installing it.
The engine/tranny has to be "neutralized.
Takes maybe 20 minutes.
Support the bellhousing with a jack. Raise it up a little until you see the mounts stop being compressed so hard.
Loosen the trans/bellhousing bolts - all of them, top and bottom - BUT only loosen them about 1/8" - 3/16" -- DO NOT BACK THEM OUT OR REMOVE THEM.
Notice the space between the trans and bellhousing. The top and bottom space should be the same IF it's in the "neutral" position. It won't be.
Now lift or lower the jack slightly - notice how when lifting you get the space at the top, none at the bottom, and visa-versa.
You want to take out the "sag."
Adjust the jack till that little space is EQUAL all around - including the sides. Now the trans is properly aligned. A little at a time, draw the bolts down criss cross pattern till tight, then torque to specs.
That slight mis-alignment times the length of the input shaft puts alot of strain on the shaft and pilot bushing/bearing, and causes the disk to not sit perfectly flat. One side of the disc touches harder than the other - chatter time.
It also helps the pilot last longer as well as the trans input bearing.
We are only talking thousandths, but it's important.
The small clearance between the bolt holes and the bolts can get the alignment way off if you aren't careful.
Even when attaching a T-Case to a Trans, or a bellhousing to the block the same caution should be taken to "neutralize" it.
It's the same idea as when you install a U-joint - and you give each ear a healthy whack with a hammer to "neutralize" it.
It's our fault - When we are installing it, after fighting to get the input through everything and get the bolts lined up, we are usually so excited we just run the bolts down tight, without ever thinking of alignment.
To do it right - after it's all installed and you've run the engine and operated the clutch a few times - THEN neutralize it.
It sure makes a big difference.
The first few hundred miles are critical to NOT let it chatter. Otherwise it will develop a wear pattern that it will make it always chatter.