mx5cartalk.com

Hey everyone,

In neutral, with clutch disengaged, there is an audible whirring/whining noise. Goes away when I depress the clutch. Master and slave cylinders were done late '13, fluid was changed circa November '14 (both box and turret). From what I've read, this could be the throw out bearing. As far as I know, everything is original and hasn't been replaced over the life of the car. How likely is it that it is the bearing? Could it be something else that I've missed? I read that it would also be coming from the diff, but I feel it's directly related to the clutch.

Another noise is at certain RPMs, in either 3rd, 4th or 5th, a very loud rattling noise (either upon acceleration or letting the car roll in gear) can be heard. Goes away if I ease off the go-pedal a bit. My mechanic said this comes from the springs:



I will eventually change the clutch and get a couple of other things replaced at the same time

Cheers,
Chris

edit: I'd probably go ahead and get the collaring, pilot bearing and spigot bearings replaced too (which some, from memory, come with some clutch kits)

Dundy2456 wrote:Hey everyone,

In neutral, with clutch disengaged, there is an audible whirring/whining noise. Goes away when I depress the clutch. Master and slave cylinders were done late '13, fluid was changed circa November '14 (both box and turret). From what I've read, this could be the throw out bearing.

Noise in neutral with clutch pedal out is most likely gearbox input shaft bearing.
Noise with clutch pedal depressed is probably throw out bearing.

Cheers

Oh I'm an idiot. The whine is when the clutch is engaged (pedal up) in neutral. Depressing the pedal results in the whine going away.

In the case of a worn gearbox input shaft bearing, is it more expensive/painful/difficult to try and fix this with replacement parts, or should one just get another box?

slug_dub wrote:In the case of a worn gearbox input shaft bearing, is it more expensive/painful/difficult to try and fix this with replacement parts, or should one just get another box?

I, too, would like the answer to this!

Dundy2456 wrote:

slug_dub wrote:In the case of a worn gearbox input shaft bearing, is it more expensive/painful/difficult to try and fix this with replacement parts, or should one just get another box?

I, too, would like the answer to this!

I had this problem with my first box, though i was running about 230hp, noise when not depressing the pedal. It decided to eat a few teeth after about 2 weeks after hearing the noise.
Replaced it with a NB8A box (paid ~$350) and has been fine, handling the current 280hp, for about 3 months.

5-Speed g/boxes are cheap, just last week some awesome forum member even dropped a decent condition 5-speed NA8 box to my house for $150, as i needed a spare.
I have read that the NB8A 5-speeds have slightly wider gears, aswell as being younger in age.

Sourcing a rebuild kit might be harder and more expensive than a good condition NB8A box.

Cheers,
Ken.

Wow thats not long from noise to damaged teeth! Mine has been making the noise for at least a year and a half, but I have less than half the power of your car

I don't really mind buying another box, I'd have to be right on it to find a bargain like you're describing though.

For 350 I can have an NA6 box off a shelf tomorrow that I would probably know approximately its age if not its usage... an NA8 gearbox more than 400, NB8A box more than 500... versus a real bargain from the forum at some point in the future but might not know the age.
If a rebuild of a gearbox is $100 in parts and my time, I'd choose to do that.

I do have a dismantled NA6 box that i got for free from another forum member. I was going to rebuild it for a spare, but then found the NA8 box.
Apparently just needs new bearings and synchros, but would be a good box to rebuild in the meantime while still being able to drive your car.
Will give it away for free, if anyone is interested.