6 speed gearbox oil leak

[Procar Specials]

maybe some of you know that I installed a new NSX-R 6 speed gearbox with some nice goodies some weeks before.

That swap is great and really works fine......so far.

I installed a CT lockout controller, which I purchased 2 year before I did the conversion now, but this part doesnt work right.
Now I have to look for an replacement part, because its nearly impossible to hit the 5th gear.


Since yesterday I have another problem, which I never have heard about before.
On my trip to the Nürburging, (it was very early into the morning and the autobahn was free) I tested the highspeed (280 km+) for many times and later I noticed lot of transmission oil overall at the gearbox peripherie, the diffusor and even at the left rear wheel.

During the installation I installed a new seal (91207-PR8-005) which seals the left drive shaft to the gearbox.

Looks like the oil comes from that section.
1th thought was that the NSX-R gearboxes maybe you another seal which is
different, but I found no different part at the part catalogue.
All 6 speed gearboxes incl NSX-R have the same seal as NA1 5 speed gearboxes.

Now Ive heard that is 'normal'......?????

The MTF mist is typical 6MT phenomenon.
It won't happen on 5MT.
On 6MT, all of them will show the MTF oil mist once you exceed about 250kph. It won't happen at lower speed such as 150kph.

There is a way to fix this but you have to open the gbox.
The simple solution is to extend the MTF breather tube and create some sort of oil catch tank.

Someone have experience with that or did that already?

 

[goldNSX]

Interesting. I had this two years ago on the BAB but with a 5-speed. I also suspected the seal between the axle/gearbox plus
- oil filter o-ring
- generally too much oil in the gearbox
I corrected all of them and had no problems since. But again, it's a 5-speed.

 

[Procar Specials]

oil filter o-ring

????

Well, I'm 100% sure that the seal which is between gearbox and drive shaft
section has a proper fit, no damage.
I personally installed it with an mechanic, so there was no contact with the drife shaft, which is mainly the reason for a damage.

So nevertheless I will install a new seal, lower the oil level and and change that oil filter o-ring, finally I will install a larger MTF breather tube and install a catchtank.

Finally I have driven the JDM NSX-R many times at highspeed, but never had had such a problem.

Ive sold many 6 speed R gearboxes last few years, but no single problem.
Maybe I'm driving too hard and fast :smile:

Attached there is a picture, which shows the breather hose.
Maybe you can sign in the oilfilter which you mean.
MTF strainer (filter)
O-ring: 91307-PR8-005
Strainer Cover: 21261-PR8-000

 

[Procar Specials]

The breather tube is here (marked)

 

[goldNSX]

MTF strainer (filter)

I meant the o-ring of the strainer.

 

[Procar Specials]

Think I have found the source and the reason after a long search.

Will report later.

But its definately not the seal!

 

[Procar Specials]

Interesting. I had this two years ago on the BAB but with a 5-speed. I also suspected the seal between the axle/gearbox plus
- oil filter o-ring
- generally too much oil in the gearbox
I corrected all of them and had no problems since. But again, it's a 5-speed.

Also interesting that it happened at a 5 speed too.
I've never had that problem with my 'old' 5 speed gearbox, even if I drove very hard and fast.

So, because my JDM NSX-R gearbox is new, I can exclude that it is the oil filter o-ring.

I'm still waiting for some eMail replies, I wanna read if my guess is right.

Because not much people in USA or other countries have the legality driving topspeeds (280 km/h+) for some minutes again and again, this 6 speed gearbox phenomenon seems to be not very common.

BTW:
I'm still looking for a CT plug and play 6spd lockout controller.....
noone seems to have one.
Ive purchased a new one from a member here, but it has a defect.

If the engine is in high rev range (+ 7.000 rpm), I dont find the 5th gear.
I'm sticking too wide at the right side above..... and there is 'no man's land'.
Even with maximum sensitivity it doesnt work.

 

[greenberet]

Also interesting that it happened at a 5 speed too.
I've never had that problem with my 'old' 5 speed gearbox, even if I drove very hard and fast.

Just as a data point, my 5 speed gearbox stays completely dry, even at speeds over 280 km/h. [edit: using Red Line MT-90 transmission oil - I haven't tried the white cap Honda MTF3 yet]

I don't know whether it's relevant or not, but the transmission oil does get quite hot. I installed a VDO oil temperature sensor in my transmission drain hole. With the stock engine oil cooler, no transmission oil cooler, and no undertrays, the transmission oil doesn't get hot as quickly as the engine oil, but when you get off the throttle, it doesn't cool down as fast, either. Several top speed runs, one after the other, may give the engine oil enough time to cool off, but they push the transmission oil temperature higher and higher. So the oil will at least get thinner.

 

[goldNSX]

Also interesting that it happened at a 5 speed too.

Well, I knew I had two 'weak' points, the left oil seal and a little bit too much MTF3 in the gearbox, maybe 1-2 dl. This could explain it all.

 

[ScienceofSpeed]

hi Detlef -- Regarding the lock out box, we've had problems with these in the past having the pins back out in the factory connector plugs, or having the wires back out of the butt connector (especially the 12-10 ga butt connector that has several wires on one end of the connector. Please check these to make sure your electrical connections are good.

thanks,
-- Chris

 

[Procar Specials]

hi Detlef -- Regarding the lock out box, we've had problems with these in the past having the pins back out in the factory connector plugs, or having the wires back out of the butt connector (especially the 12-10 ga butt connector that has several wires on one end of the connector. Please check these to make sure your electrical connections are good.

thanks,
-- Chris

Chris,

thanks for your input.
I removed the unit already and checked all pins.
All is fixed and seems to be OK, so something other is wrong with that part.

Havent thought it is so problematical to get another CT lockout box.
They seems to be not available, I wonder how all conversion will be done into the future.

I had a spare part which I sold already, now I do regret that heavily!

How you you test if such a unit is still OK?
Please tell me the procedure, I appreciate any helf.

BTW......this CT kit is plug and play, yes, but you have to take care during installation.
2 connectors at that box are male, the speed sensor and the lockout sensor.

Even they are different because the speed sensor connector has 3 cables and
and the lockout sensor has 2 cables, they can be interchanged.

What happens if that happens?
Only a question, I have checked that before and we finally did no mistake,
but I wonder about all other conversions?

 

[Procar Specials]

Yesterday I did a solenoid test at the new NSX-R gearbox.

I connected the reserve lockout solenoid with power and ground at 2 pins like discripted in service manual 13-11, so a klicking sound must be heard.

So, there is no klicking sound, means that I have to change that part too.

Looks like the broken CT lockout controller has broken that expensive part too.

Now I have to drain the gearbox oil again (the 3th time) and it looks that there is no end until all problems are fixed.

Its also a pain in the ass to get a new working CT lockout controller.

 

[Hrant]

Detlef, check your e-mail :wink:

 

[Procar Specials]

Hi Hrant,

thank you very much, Ive emailed you back :smile:

Havent thought that its so difficult to get a 'working' system, but the NSX-R gearbox is worth all additional work, thats for sure.


Finally I'm happy that I did that basic solenoid test.
(Never heard about that kind of damage but there is always something new....)
but now its clear why I couldnt manage to shift from 4h into 5th at high rpm.
That also means that I also could shift into reverse at each speed, a nice idea :smile:

Even a new controller hadnt fixed that.

 

[Procar Specials]

Today I installed the gearbox breather tube extension system with catchtank and special heat resistant hoses.

I also changed the MTF3 oil to a motorsport oil wit other specification and reduced the filling.

The idea is:
After some more high speed tests next few weeks I will drain that system and look if there is some oil into it.
I also installed an overflow system from catchtank to nowhere, but I'm sure
that its not requested.

Finally I will remove the complete system if I dont will find oil into it.

Here is the result:

 

[Procar Specials]

One of my customers in UK sended me his CT 6 spd lockout box for testing.
He bought it 3 years before new from CT and stocked it because he hadnt the money for the gearbox til now.

Yesterday evening I tested that unit.

What a shame....it doesnt work too.
Same malefunction as the other one.
Now I have 2 of these damn controllers.

 

[Procar Specials]

....in the meanwhile, 2 more european NSX owners contacted me because their CT controllers shows the same problems.
These boxes are on their way to me too.

So, 4 customers in EUROPE have problems with that part.

My friend, an electronics technician will visit me this friday and we take a look at these parts.
We dont will stop work this weekend until we find out the reason for malfunction, the NSX must run again at sunday.

We will repair the other boxes too and charge only a very small amount for labour.

The final decision is that PROCAR SPECIALS will produce a 'working' 6spd lock out box with original plugs and offer them soon at the market.

I dont will waste more money and time to get a working part from the manufacturer in USA.

Thanks to Larry Bastanza, who have sold me that part and tried to get an replacement part for me.
Finally that mission was successless until today, so I paid a high price
for nothing.