New owner of a 1998 NSX, gearbox noises anyone ?

[Matt1212]

Hi there!

I would like to ask to people if they get noise from your gearbox / tranny when driving. Sometimes in lower RPM it reminds me of my dogears in my K24 race car. Some clunking too... very hard to describe but it sounds like a race car.... I dont have any shifting or clutching problem. Brand new SOS 275 clutch kit installed. The car has only 19 500km.

Is it common with NSX because I never drove one before and I dont have anyone around that did.

Thanks !

 

[dmartin149]

Mine is a little noisy in 1st & 2nd. No klunking, just some zing. It has pretty low miles and is a SOS short gear 5sp. I don't know if that's normal or not.
I'd be interested in what others have to say too.

 

[Old Guy]

I find that the 6 speed drivetrain on my 2000 has a fair amount of klunk / drivetrain lash which is most noticeable at lower RPM in first and second gear. Can make driving smoothly in stop and go traffic a hassle. At first I thought it might be badly worn driveshafts; but, inspection showed the driveshafts were nice and tight. I have had the car since 2011 and nothing has changed (now at about 125,000 km) so I deduce that this is just the way they are. About 12 years ago I asked the NSX certified service tech at my local dealership about it when getting an oil change and his comment was 'that is just the way they are'.

There is no howl from the transmission which might be a characteristic of a dog style box if it was using straight cut gears. If you are getting howl / whine all the time I might be looking at a transmission bearing issue or perhaps the release bearing on the clutch.

Brand new clutch after less than 19500 km does smell like somebody abused stuff (or perhaps they didn't adapt to driving with the NSX's high release point) so that does open up the opportunity for lots of issues that are not common. If it has been abused to the point that the clutch was toasted you might want to check those driveshafts.

 

[Matt1212]

I find that the 6 speed drivetrain on my 2000 has a fair amount of klunk / drivetrain lash which is most noticeable at lower RPM in first and second gear. Can make driving smoothly in stop and go traffic a hassle. At first I thought it might be badly worn driveshafts; but, inspection showed the driveshafts were nice and tight. I have had the car since 2011 and nothing has changed (now at about 125,000 km) so I deduce that this is just the way they are. About 12 years ago I asked the NSX certified service tech at my local dealership about it when getting an oil change and his comment was 'that is just the way they are'.

There is no howl from the transmission which might be a characteristic of a dog style box if it was using straight cut gears. If you are getting howl / whine all the time I might be looking at a transmission bearing issue or perhaps the release bearing on the clutch.

Brand new clutch after less than 19500 km does smell like somebody abused stuff (or perhaps they didn't adapt to driving with the NSX's high release point) so that does open up the opportunity for lots of issues that are not common. If it has been abused to the point that the clutch was toasted you might want to check those driveshafts.

The noise that feels like a dogbox isnt all the time. I dont think its the driveshafts... I bet from what I read that it might be normal. The car is very low km so... I guess all is good. The fact that the motor / tranny is just behind might get me more noise than a regular car too.

Cant wait to drive the car more...

 

[Honcho]

The noise that feels like a dogbox isnt all the time. I dont think its the driveshafts... I bet from what I read that it might be normal. The car is very low km so... I guess all is good. The fact that the motor / tranny is just behind might get me more noise than a regular car too.

Cant wait to drive the car more...

You might just be experiencing the awesomeness of having the powertrain directly behind your head. In all seriousness, the 5-speed and 6-speed should be fairly quiet. If clearanced properly and with good synchros/hubs, the trans should have little to no noise. My NSX-R 5-speed that I fully rebuilt is silent, though there is a bit of gear lash in 1st. You can't feel it in the car (no clunks) but if you spin the tire by hand while in gear there is some movement in the gear stack. I have noticed the NSX-R differential can get a little noisy in slow parking lot turns, but your 98 has the helical planetary gear set in the diff so it shouldn't be loud.

Typical culprits for NSX gearbox noise are:

• Countershaft top bearing (groaning or pulsing)
• Mainshaft top bearing (groaning or pulsing)
• Synchros/hubs (grinding noise when shifting)
• Differential/axle bearings (groaning or pulsing)

This is due to the layout of the NSX's transmission design. The transverse setup and position of the two gear stacks mean the outer ends of the shafts see an angular load and more potential for movement. If you're getting a groaning or whine noise, it's probably one of the above items. The NSX 5-speed and 6-speed are some of the finest manual transmissions in the world, but they also do wear out like anything else. The 6-speed may have a little more gear lash since the gear stacks are longer, but to be honest I've never heard it in a 6-speed either.