I have a 2007 4-door JK with the NSG370 manual trans - it's only got 150k on it but feels like it may need a rebuild. :-p
When the Jeep is stopped (engine turning or not), one or more gears can be impossible to shift into - sometimes all gears are impossible to shift into - and when it finally does, there's a definite "clunk" in the drive-train.
The NSG370 trans has never been great - sometimes popping out of 1st, sometimes difficult to shift into 2nd - the synchros might be worn.
Since the clutch master/slave cylinders runs on brake fluid, I had the brake fluid changed and the master/slave bled to make sure the clutch was disengaging properly - it was a long shot, and although it seems a bit better, that's probably from the transmission fluid change, which was done at the same time.
So, I'm guessing the NSG370 needs a rebuild, and wondered if there are any good manual transmission rebuild shops in the lower mainland?