Nissan clutch problem

You have not indicated whether your car is a stick shift or an automatic transmission.
If it is a stick-shift, look for a problem with the master cylinder or the slave cylinder on the clutch.
The clutch is actuated by hydraulics, and loss of brake fluid from the system will cause the car to stop shifting.
The master cylinder for the clutch is smaller than the brake master cylinder, and is mounted under the hood (in front of your knees while you are driving).
The slave cylinder is mounted on the transmission near the clutch assembly.
More often than not, the slave cylinder fails before the master cylinder.

If your transmission is an automatic, and the fluid is correct on the transmission dipstick, you may need a transmission overhaul, which can be very expensive.
God bless your efforts.

From your description, it sounds like your out of or very low on fluid.
Use brake fluid. There shluid be two silver cylinders with plastic covers on them. On cylinder will be much longest than the other. The short one is you clutch master cylinder. Pull the cap off of it and see if it has any fluid in it? If it is at least one third full than you shouldn't be experiencing that problem, in which case you would be wise in bringing it to a repair shop. If there is no fluid, pour brake fluid in it , put the cover on it and hand pump the pedal. if you feel resistance and the pedal no longer stays on the floor, top off the cylinder and you might be able to drive it to where an auto parts house can look at it ( they are in the business of selling parts, so it is in their advantage to sell you parts you need and might even be able to sell you a cheap set of tools to do the job with. There a manuals published which cover most makes and model cars. You may find one on your car there. Good luck

on the bottom of the clutch housing there is a bleed nipple, like on the brakes, if you have pumped the clutch with out enough fluid in the brake receiver container you would of put air in the clutch system, you need to keep it topped up all the time so its at max. and bleed the clutch, you will need to lift the clutch pedal by hand up and down a few times to get the air out, its not assisted like the brakes so it will take a good few pumps and tightening the nippel when it feels pressure.

Ok Matt,I got you covered,when your clutch master cylinder goes empty,your clutch slave is leaking and not holding pressure,you can fill reservoir and bleed to get you home,I've did it in my 85 nissan 720 4x4 before,you can have someone pump clutch pedal a few times and hold to floor and you open bleeder valve at slave cylinder till air is gone,just don't let resevoir get low.Here is a link to bleeding,your slave cylinder is bolted to side of transmission with 2 bolts.Be careful and don't strip bleeder screw,you can get part at Autozone,also get dot 3 brake fluid,this autozone iis not showing a guide to replace,here's one from a 85 nissan,very similar.

Sound like you're going to need a whole new clutch assembly, but if the fluid level was dry you may have sucked air into the system which means that the clutch will have to be bled at the slave cylinder, just like you would brakes. The squealing sound is coming from the throw out bearing, usually when the do that it means that the bearing is frozen and cannot spin. Either way it looks like you'll be dropping the transmission to work on the clutch.

on the transmission there is a slave cylinder that works like a brake cylinder, when you apply pressure to the clutch pedal a rod inside the vehicle under the dash pushes into a clutch master cylinder, (almost like a brake master cylinder without the reservoir, as the clutch master cylinder works off the brake master cylinders reservoir) the plunger in the clutch master cylinder applies fluid pressure to the slave cylinder,(located down on the trans near the clutch fork assembly) which projects a piston rod into the clutch fork dis-engaging the clutch. To bleed the clutch slave cylinder locate the bleeder screw on the slave cylinder,break loose so it loosens and tightens easily. Check fluid in brake master cylinder reservoir,fill if needed, while bleeder on the slave cyl is closed have a helper push clutch pedal to floor and back 7-8 times, (At first the clutch might stay at the floor, just pull it up by hand or foot and continue) after several pumps with no rest time push pedal to the floor and hold down with foot pressure, at this time loosen the bleeder on slave untill fluid leaks out, watch for air bubbles, close bleeder and repeat untill there is no sign of air bubbles, (make sure to check fluid in the brake master cylinder and keep fill as needed, do not let fluid get less than 1/2 empty as it might **** air and you will have to start over) If this does not bring clutch to operate then you need to check if slave cylinder is reachig its full extension of push rod or not. If it is not then you will have to replace the clutch master cyl or the clutch slave cyl or both as seals are bad and wont hold pressure. Or you need to inspect the clutch fork,the throw-out bearing, or the pressure plate fingers and clutch plate for failure or broken bent parts. I hope it turns out to be a easy fix on that clutching thing.

I believe your pressure plate is broken and at a minimum will have to be replaced along with the clutch disk.

I am dealing with a very similar issue on my 03 Spec V , So far i noticed the clevis pin was loose and the locking hitch pin that slips thru it had fallen out . this caused the gears to not wanna engage due to the bolt behind the clevis which runs to the master cylinder was not getting pressed in when i pushed the clutch pedal in because the clevis pin was slippin on n off giving me no pressure up top .. I had to remove my lower dash panel in order to get visual n hand access to this pin , it is a tight spot to work in as well . May be easist to remove the 4 14mm bolts that hold yur driver seat in to give ya more room to work n stretch out ur arms

you may have a weak clutch master cylinder

Put your foot on the brake pedal hard and then shift it out off park mister bill