While driving today I started hearing a squeaking/grinding sound when I shifted and sometimes for a couple of seconds after. When parking the last couple of feet it popped back up and sounded like a really nasty grinding noise. I let it sit for about a half an hour and hopped back in to test it out, here is what I found:

Sitting in neutral produces no sound. Depressing the clutch causes a very low volume grinding noise. Shifting gears is hit or miss for noise, sometimes it shifts perfectly and at others I get a noise as if I bottomed out and scraped against the pavement and the final time I got a noise like something was slipping (a fairly quick WHHEP WHHEP WHHEP with a low grind behind it).

The only recent things I have done that I could see being remotely related is a replaced a bad slave cylinder about a week ago. From everything I've read it sounds like a bad throwout bearing, is that so?

 

Further reading seems to indicate that the pilot bearing may be the culprit. How could I narrow down which to attempt replacing first?

 

Typically a pilot bearing only make noise when the clutch is depressed (its literally stationary when the clutch is engaged) When you are not in a gear, does any noise come or go when depressing or releasing the clutch? Is it hard to shift at times, like the clutch isnt releasing? simplest things first, reinspect the clutch master and slave cylinders to see if there is any obvious seepage/leakage, secondly just for ***** and giggles re-bleed the slave cylinder and see how it feels/shifts

 

You need to remove the transmission to change either one so when it is out being as they are both inexpensive parts might should change both anyway . throw out brg is probably dry and making bitchy noises .

 

I'm thinking it's that or the pilot bearing is dry. I decided that while I'm at it I might as well replace the entire clutch since I'm about to make a cross country trip. What should I use to grease the bearings?

 

Good idea to do the clutch while it is out . Any good quality grease will do the job , grey lithium is readily available and is a good all around lubricant . More important is to make sure you do a nice job on the pilot brg, seal ( make sure you order one when you get parts ) . clean the seal surface well so you don't need to fight with it during seal instillation and end up screwing it .
Make sure you check your U joints when the drive shaft is out .

if you don't already have one you can download the FSM for your vehicle here , http://rx7.foxed.ca/