I drive a 1988 Mazda RX-7 non-turbo 5spd.

The previous owner claims the clutch was done last July(little under a year ago) and I have no reason to doubt such claims. I do believe the clutch release bearing was not installed correctly. When the clutch is not pushed in, there is a spaceship kind of noise(almost the noise a EV makes when accelerating). When I accelerate there is the same noise. However, when I put the clutch in the noise goes near silent. It gets louder the higher the RPM when in neutral.

I am no mechanic, however after some searching on the internet it seems to be the clutch release/throwout bearing. I am pretty tight on money so I would like to hold back on the repair as long as possible without causing any serious damage. I can imagine that I would be racking up the labor costs and I am not equipped to do the job myself.

The question is, what happens if the clutch release bearing completely fails? Will there be collateral damage to anything else or will I just find myself unable to shift?

3 Answers 3


The noise you describe is a VERY common issue with the transmission in the model of RX-7 you are driving. As a matter of fact, my current RX-7 (1991, 220k miles) has this exact same issue.

Based on your description, the noise is almost certainly coming from the transmission's input shaft bearing - not any part of the clutch assembly, or anything that would have been replaced during a clutch replacement. The only true fix for it is a disassembly of the manual transmission itself, and replacement of the affected bearing.

Essentially, all you can really do between now and eventually replacing that bearing is to keep the gearbox oil level full and clean. Some suggest trying different oils (e.g. Royal Purple) but that would only (if anything) reduce noise, and is not really addressing or repairing the issue. The good news is, it's not typically an issue that will cause you to "get stuck somewhere" unless it gets bad enough for the bearing to completely fail (unlikely as long as you keep that fluid clean and full!). You can usually drive with it making that noise indefinitely.

  • Not the answer I wanted to see, but it makes sense. I'm getting the clutch done this weekend since it slips so maybe if I'm dead lucky it's the TOB.
    – Alec
    Jul 9, 2015 at 19:39

If the noise is only happening when the clutch is engaged (pedal out), it's not the throw out bearing. You'd only hear the noise when you push on the pedal. This is because the only time the throw out bearing is being used is when you are pushing the pedal down. It won't contact the clutch fingers any other time, and therefor cannot make noise with the clutch engaged. The noise you are suggesting indicates to me the front bearing in the transmission is on the way out (or has expired).

EDIT: To actually answer your question about the TOB ... If the TOB fails, it will ultimately be destroyed (assuming the TOB stops spinning as designed when engaged). When it stops spinning, it will in turn destroy the clutch fingers. This will entail a complete clutch replacement, sans the flywheel (unless it needs replaced for other reasons).

  • I am fairly certain that the noise is not coming from the transmission because it still occurs when I am moving, and if I put the clutch in it goes away. I saw an explanation online saying when the bearing doesn't have stress on it it allows play which makes the noise, and when the clutch is put in it puts pressure on the bearing which forces it to work despite the play. My question is what will happen if the bearing fails, not what's wrong with my car as I am fairly certain it is the throwout bearing.
    – Alec
    May 19, 2015 at 3:35
  • @Alec - I can add to the answer what will happen with a bad TOB, but you are barking up the wrong tree as far as your diagnosis. The TOB will only make noise when you are pushing the pedal and the TOB is pushing on the clutch fingers because that is the only time it's actually being used or turning. It cannot make noise when it's not engaged, because it's not doing anything. Just saying. May 19, 2015 at 10:43

if the TOB fails, you will usually hear a loud grinding or squealing when you depress the clutch pedal. Eventual failure will destroy the clutch pressure plate, and clutch disk, and could possibly damage the throwout bearing lever, which could punch a hole in your bell-housing, or damage your flywheel.

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