gaerbox issues

[214nsx]

Kaz,
Thanks for that. In neutral there is no noise, clutch engaged and disengaged. When you put it in first or reverse noise starts quickly but not constant as if something is rotating and then catching. In the Midlands if anybody knows of anybody with experience of the NSX G box. I will double check the oil spec.

Gurinder

My 91 Nsx recently developed the same noise as you described, rolling speed forward or backward, noise coming from left hand side/ Gearbox. No noise when car is off the ground. Car starts fine, butter smooth select in any gear. Had the passenger side driveshaft inspected by a mechanic but found nothing abnormal.

Gurinder, please report back if you managed to fix your and ill do the same.

Phil

[bainsgs]

Will do. They did use the MTF-3 oil so nothing untoward there

[214nsx]

Hi Kaz, Where is the MTF meshed metal filter located?

Phil

[Kaz-kzukNA1]

The location.



If the noise is from the DF, probably inspecting the strainer won't tell much.

There is a big magnet plate near the MTF pump so any big particles would be trapped there.

At the strainer, normally you would only see tiny particles from the synchro or gear teeth edge or anything that doesn't stick to the magnet such as the liquid gasket.






You'll need the replacement o-ring and the MTF filler washer.

The drain washer is the same one used at the oil pan/sump drain.

If never done before, good idea to get spare cover as you could break the tab.








If not treated in the past, by now, the blue section of the strainer cover is already heavily oxidised and bonded to the trans case.

This makes the removal of the cover time consuming if not done previously.

On installation, just coat the blue section and the backside of the tab with the silicone grease.

Never apply leverage force trying to lift the cover using the tab marked in red.

Instead, apply force in the direction marked in yellow to 'rotate' the cover back and forth.

This will break the oxidation and while trying to rotate the cover, change the direction of the force just a little to pull the cover outwards.

Repeat it and eventually, it will come off.






The example of what you would expect inside the strainer.

Just a tiny metal bits with metal powder.






The worst one so far….. It's not metal and in fact, excessive amount of liquid gasket.


Kaz

[214nsx]

Thank you Kaz��

[214nsx]

So just a little update on my side. I replaced the diff oil from Honda MTF-3 to Royal Purple and the noise had disappeared.

[Kaz-kzukNA1]

Thank you for the update, Phil.

Interesting. OEM DF (differential) or aftermarket one???

I know fair amount of owners in US used 'cocktail' mix for the MT oil when they experienced difficulty in gear shifting.
For me, this is just hiding the issue and not a fix because for street driving, one should not have any shifting problem with the Honda MTF3.

Some even reported new issue on DF by using the cocktail method despite the significant improvement on the shifting difficulty.


The earlier spec DF has multiple CL disks with embedded friction material and soaked in the MTF.
It's pre-loaded and constant locking force regardless of the input force difference between the R & L shaft.
The spring washer/plate sets the friction force and the locking won't start slipping/break out until after exceeding the pre-loaded torque.

So, using different MT oil will change the characteristic of the locking/slip behaviour.
For the clarification, this doesn't mean good or bad on the DF friction disks.

Would be interesting to hear the update in longer term as I know some owners in Japan are using customised RP fluid in their MT box.


Kaz