whirring noise in gearbox

stevesports · Postby **stevesports** » Thu Mar 13, 2008 11:20 pm

Any NB8B guys, can you try something for me?
can you find a quiet sort of place, go up to like 50-60km/h, get out of gear and into neutral, release and clutch and try to engage first gear. Now don't exactly try to get into gear, but apply a little force so the synchro is engaged. Tell me do you hear a whirring sort of sound, kind of like 2 straight cut gears are moving together?

i mean is this normal? are the synchros supposed to make that noise?

Alex · Postby **Alex** » Fri Mar 14, 2008 1:46 am

I must say trying to push into 1st while going at 50-60km/h doesn't sound like my gearbox's idea of fun

if it only happens under the conditions that you mentioned then I wouldn't be worried
if not then post up what you are actually doing when you hear this sound

stevesports · Postby **stevesports** » Fri Mar 14, 2008 7:47 am

sorry i don't mean actually engage first gear, but place a little pressure on it such that the synchros spin up.

i also hear this sound when i'm in first gear and i'm accelerating. This also occurs but to a lesser extent in 2nd and to an even lesser extent in 3rd.

JBT · Postby **JBT** » Fri Mar 14, 2008 8:22 am

Normal.

wun911 · Postby **wun911** » Fri Mar 14, 2008 8:48 am

normal mechanical noize?

bruce · Postby **bruce** » Fri Mar 14, 2008 10:23 am

Sounds normal to me.

Stupid thing to be doing to the poor box.

silvermiata · Postby **silvermiata** » Fri Mar 14, 2008 10:32 am

erven if anything is starting to go wrong with the box, you dont need to worry for a long while

is it a whining noise like a supercharger or whirring?

Uncle Arthur · Postby **Uncle Arthur** » Fri Mar 14, 2008 12:36 pm

stevesports wrote:Any NB8B guys, can you try something for me?
can you find a quiet sort of place, go up to like 50-60km/h, get out of gear and into neutral, release and clutch and try to engage first gear. Now don't exactly try to get into gear, but apply a little force so the synchro is engaged. Tell me do you hear a whirring sort of sound, kind of like 2 straight cut gears are moving together?

i mean is this normal? are the synchros supposed to make that noise?

Sounds like you need a new hamster.

stevesports · Postby **stevesports** » Sat Mar 15, 2008 5:18 pm

whining noise sorry. Kind of like a supercharger i guess. I can tell it is the synchro spinning up.

JBT · Postby **JBT** » Sat Mar 15, 2008 5:22 pm

The gearbox is trying to tell you \"don't do this to me!\"

stevesports · Postby **stevesports** » Sat Mar 15, 2008 7:29 pm

Let me explain it this way, there is a whining noise when i am in first gear and accelerating. It is less prominate as i move up the gears. Faint in 2nd gear, even less audible in 3rd and inaudible in 4th. In addition, the sound decreases as the gearbox warms up.

the reason i explained the above situation is to isolate the problem. As i said, i've narrowed the noise down to synchros (which i think is correct).

JBT · Postby **JBT** » Sat Mar 15, 2008 7:35 pm

You would have to ride in/drive another similar model MX-5 under the same conditions to see if what you're experiencing is normal or not.

It's impossible to draw worthwhile conclusions on a chat board.

silvermiata · Postby **silvermiata** » Sun Mar 16, 2008 11:02 am

i had the same problem/ have the same problem... its a bering failure in the gearbox (i think countershaft bearing)... i had the same small noise about a year ago.. and now its quite audible...

typical problem with mexy gboxes... you can find topics with the same problems in miata.net forums....

bensale · Postby **bensale** » Sun Mar 16, 2008 11:20 am

One thing that can contribute to gearbox noise in the mx5 is the proximity of the gearbox to yourself.

I know my NA6 has a bit of gearbox noise, as does ever one i've been in so I would say its typical. I've never been in a nb so I cant on them.

I would recomend a back to back test, maybe take a mate down to a car yard with a nb and go for a test drive.