NB & NC Automatic gearbox reliabilty ?

Code4 · Postby **Code4** » Sat Apr 09, 2016 6:24 am

While I realise this forum is mainly composed of performance enhancement posts for road and track, I was wondering about the reliability experiences of members who have autos in the NC MX-5.
The minister of war and finance has stipulated an auto :roll:

hks_kansei · Postby **hks_kansei** » Sat Apr 09, 2016 7:56 am

What will the car be used for?
Modified?

For regular use I've not heard of any mx5 autos having any big issues, even NA with heaps of km on them.

In general autos often tend to be stronger than manuals since the auto just slips if too much power goes through, where a manual just breaks a gear.
The usual killer of autos is heat, which is why often cars that tow for trans coolers

Unfortunately I can't give anything specific to mx5 autos.

From memory the NA NB auto was mostly the same box as in the Mazda 929. And I haven't heard of them with auto issues (more power than an mx5 too since they were v6)

davekmoore · Postby **davekmoore** » Sat Apr 09, 2016 8:12 am

NB with auto is not really an MX-5.

NC with auto still spoils an otherwise excellent car, but is not as bad as an auto NB.

project.r.racing · Postby **project.r.racing** » Sat Apr 09, 2016 9:16 am

Its like most of the automotive world. 90s auto boxes are horrid and just useless in applying the power. Mid 00s boxes just improved so much.

Mr Morlock · Postby **Mr Morlock** » Sat Apr 09, 2016 11:15 am

NC autos with paddle shifters are a terrific way to enjoy a sporty car and far easier in traffic- I have dríven them and like them. A high proportion of NDs are being sold as autos and virtually all performance cars are supplied with autos- many don't even offer a manual change. In larger cars like Holdens or Fords the manual is a resale liability.Automatic MX5 NC reliability should not be a problem and no clutch to wear out . Go for it- great idea and with the partners blessing - great I cannot think of a downside including driving- mates who own them give them a big tick. PS don't buy an NB auto it was old school engineered.

Code4 · Postby **Code4** » Sat Apr 09, 2016 1:41 pm

Thank you for those informative replies.

Postby **NitroDann** » Sat Apr 09, 2016 5:06 pm

Get a new one.

Code4 · Postby **Code4** » Sun Apr 10, 2016 11:46 am

Found this info. Research continues.

Three different automatic transmissions used in the Mazda including the Jatco N4A-HL 4N71B ( 91-93 ), NC4A-HL 4N71B ( 94-97 ) and the Aisin A44DL & A44DE ( 99-up ). It's used in quiet a few RWD Japanese cars, trucks and SUV's.