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Today at Atelier Kaz - Private NSX Enthusiast, ex-Honda R&D engineer with F1, Indy/CART background

Cooling Sys, Health Check, etc 33

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This NSX is AT model so the ATF drain plug has magnet on its body.

I was told that the ATF was replaced in the past so quite surprised to see the amount of metal dust.


Unlike other planetary geared AT, Honda uses multiple CL discs at each AT gears submerged in ATF.
It estimates the required pressure for the next gear and controls the ATF pressure in order to let the CL discs slip to
reduce the shifting shock when up/down shifting to the next gear.
Thus, inevitably, it will produce CL disc debris over the time.

There is another big meshed filter inside the AT gbox and once these debris started blocking the filter, you will start losing the drive
simply because you can’t generate enough pressure.
Under this condition, if you park the car for a few hours to let the debris to drop to the bottom,
you can recover the drive but you won’t survive for a long before it happens again so time to overhaul the AT.


Honda changed the spec of its OEM ATF and it’s now called DW1. Used to be Z1.
It can be mixed with Z1 and DW1 has improved performance (but what performance???) under cold environment.
Although if can be mixed, I prefer draining as much old ATF as possible so kept the engine off for many days.




It’s AT model so the shaft body length is longer than the MT one and thus, took extra time for taking it out.
The white market shaft length without the joints is the same as the Right side one.
In fact, the position of the spider groove, etc are at exactly the same position.





Very rusty hub spline….
No wonder why I had to invest into the heavy duty puller.




RL wheel speed sensor head.
There was some scratch markings but no ALB/TCS warning lights so still fine.







The trans seal.

From this angle, it looked fine but I was worried about the amount of black debris around there.

Normally, I would see custard cream or melted coffee ice cream like grease splashed everywhere but not like this thin layer of black debris.
It looked as if ATF leaked from the seal and then road debris/film caught on there while the car was driven.

To be on the safe side, I’m going to replace the seal.










The same procedure for the Left drive shaft as well.
















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Driveshaft

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