I'm sure someone else has already posted a similar thread with this problem but i haven't been able to find it. My 4runner has been sitting in the backyard for just over 4 months now due to no tags. I had been going out and starting it and letting it run for about 10 minutes every couple of days but i never moved it. It was sitting in neutral no park brake on. Went out there yesterday to move it out because i am getting ready to retag it and was going to clean it up when i realized that it wasnt moving in gear. The engine just reved and when i was letting off the clutch nothing happened, no whine no squel nothing but just reving. I tried to go in every gear and every gear in 4h and 4L with hubs locked. I also realized that i was flowing thru the gears without the clutch pressed down as well. I could feel it shift into every gear but it was acting like it was still in neutral. I tried to push it around and see if it would click into gear but that didnt work. It is a fairly new clutch as i put it in back in January. I wasn't having any problems with it before now. Does this sound like a clutch problem or could this be a transmission/transfer case problem? Any help on how to fix this would be much appreciatted. Thank you.

Just a stab at it.

Before anything else I think, check if the fluid has not leaked out of clutch master cylinder.

then

Follow the clutch pedal and make sure that it is properly connected to the rod that connects the clutch master cylinder and that it doesn't remain alway pushed in, based on you description that you can change gears with out pressing the clutch. You should be able to see it under the hood going in and out everytime you press the clutch...may need a helper to push the clutch pedal.

then

Out of the clutch master cylinder you can follow the hydraulic tubing down to the slave cylinder on the side of the transmission. Check for leaks or kinks and make sure that the slave cylinder is also moving in and out and not remaining enganged...i.e. neutral...so that you can change gears with pressing the clutch pedal.