- My model of MX-5 is: mk3 NC 2.0 2006
- I’m based near: Shropshire
- I’m looking for technical help or recommendations on: Everything!!!
Morning all, am a newbie To MX5 's and have been an owner for a few weeks, haven’t been out too much in my new toy but already have the pleasure of a speeding ticket ! Getting to know all of the pleasures of owning my little pocket rocket, wet boot, bit of tin worm etc but my biggest annoyance is that I have a weepy bell housing \ transmission leak. I have been reading up on this via the forum Guru’s and have seen that there is a lot of talk about the CAS O ring failing? I can find vids on how to replace this on the Mk1 and maybe Mk2 but not on the Mk3 NC, Could anyone please point me in the right direction / advise if this is a fairly straightforward fix, hopefully with the aid of a youtube link ? I have looked but can’t seem to find anything. Ah well, back to rubbing down my rusty bits 
Many thanks.
Sounds like crank oil seal.
Easy fix once box is out.
Ah, thanks for the reply Kev. Would you know, will I do much damage by continuing to drive whilst leaking, is there any way I can check fluid levels, assume it would be gearbox oil that is leaking? Engine oil level doesn’t seem to have moved. Have you removed the box on one of these? Would be doing in my garage with basic skills on axle stands, cheers.
You can still use the car no problem but Its highly unlikey to be the gearbox leaking. whenever theres a leak from the bell housing 9 times out of 10 it will be the crank oil seal. Gearbox out clutch and flywheel of and replace the seal.
It must only be a very light leak at the moment because you say your engine oil is ok so just keep an eye on it that’s what oil it will be leaking.
It will obviously get worse and will end up contaminating the clutch ending in clutch failure (probably will start slipping if it gets that bad)
I havnt personally taken one of those boxes out but hundreds of others.
Right, ok Kev, many thanks for your replies and info.I will keep z close eye on it 
I have the same problem-local mechanic took box out /clutch/flywheel off and fitted new genuine oil seal (£120) fitted new clutch .Week later its still leaking.Was advised by expert its an awkward job (needs engine out really .) Problem seems to be locating the flywheel over the seal as seal faces “wrong way” (seal taper faces engine ) and you cant see to locate it (used a plastic sleeve to help it in ). Going to have to have another go .Very disappointed.
There is a special tool for this
http://ncmiata-servicemanual.com/ServiceManual/manual/mazda/2008/miata/g5/books/g5w01/html/id011045800900.html
1 Like