What could be wrong with my S13?(chattering/grindy noise)

[nizmo_bro]

I just bought a 92 240sx KA24DE SE Super Hicas, drives great. I really must have not noticed this problem while on the test drive, but noticed it on the drive home last night.
There is a kind of chattering or grinding noise coming from I think may be the clutch. It doesn't seem like the transmission itself. The sound from in the car seems to be more towards the front. Each gear its different.
1st seems fine
2nd the noise comes in when I'm coasting, no clutch or gas pedal pressed. Goes away when I slightly press the gas pedal
3rd not as noticable
4th has the sound come if I'm hovering around 2000RPM and give it gas
5th is kind of the same but not as loud
Neutral sounds completely fine, clutch in or out. I figured it cant be the throwout bearing then.

When I'm downshifting from 3rd to 2nd it also makes a chattery noise during the shift. It isn't a grind, like if I were to not use the clutch.
It doesn't really seem to effect the driving of the car, at least not yet. It has me a bit worried. It's not super horrible sounding as I would have really noticed it on the test drive.

previous owner put in a VLSD, but IDK if they had done anything else, like new driveshaft or anything. I at first thought that could be the sound, but I figure I would hear it on the side of me not towards the front.

Other info that may help, I dont remember the brand name, but it has a short shifter. Guy said it retailed at around $200. Super short gear changes. Maybe the person who installed it may have done something incorrectly.

I hope you guys can help me pin point the problem.

[PapaSmurf2k3]

I'd start by checking things external to the trans, like U-joints in the driveshaft and bushings and stuff.

[liquid_cool]

this could be many things, becouse we are not able to drive it and hear for our selves we will point you in the best possible direction we can..#1 papa's rite..check the u-joints.#2 check to see if the bolts that hold the transmission on are even tight#3 check fluids in the transmission..may have a leaky seal or sumpin..#4 check motor mounts, and transmission mounts..last but not least..check to see if the vlsd is mounted corectly..some require an adapter bushing...hope this helps

[nizmo_bro]

Thanks for the replies. I'm going to take a look and inspect all that tomorrow as I change the oil tomorrow.