Manual transmission oil preferences?

[Matt'sNSX]

Hello all!
With spring right around the corner I plan on un-mothballing my 96' NSX-T and change both the engine and manual transmission oils. I'm curious if anyone has any manual transmission gear oil preferences or if they just follow the service manual recommendation of an SF or SG API service grade in either a straight 30 weight or 20W40 weight (I live in the north east but it is strictly driven between spring and fall.

Does anyone have any thoughts or suggestions? All will be sincerely appreciated!


Matt

 

[JohnWayne]

Honda MTF

 

[Old Guy]

Out of curiosity I tried the GM synchromesh cocktail mix because a lot of posts were very enthusiastic about it. I didn't notice any particular difference so last time it was back to Honda MTF.

 

[ekhonda87]

I had a 2nd gear grind on my 91 so I tried the Synchromesh.
Specifically the AC Delco synchromesh 10-4006 (2 qts) and AC Delco friction modifier 10-4014 (1 qt).
The grind has not yet reappeared and there were no other noticeable changes in performance.
Long term effects on the LSD are unknown, but there is anecdotal evidence to suggest it is safe though.

 

[mwagner10702]

Honda White Cap Manual Transmission Fluid

08798-9031 - Genuine Honda Fluid, MT

HondaPartsNow.com offers the great deal for genuine Honda parts, 087989031. Fluid, MT for $6.66. All parts are backed by the Honda's warranty.

www.hondapartsnow.com

 

[Old Guy]

I had a 2nd gear grind on my 91 so I tried the Synchromesh.
Specifically the AC Delco synchromesh 10-4006 (2 qts) and AC Delco friction modifier 10-4014 (1 qt).
The grind has not yet reappeared and there were no other noticeable changes in performance.
Long term effects on the LSD are unknown, but there is anecdotal evidence to suggest it is safe though.

I don't think the synchromesh friction modified (or Red Line MTL which is similar) will damage the LSD. Because of the friction modifiers it will result in earlier / more aggressive engagement of the LSD. The friction modifiers are designed to help the synchros by increasing the grab so that they do a better job of aligning the gear teeth during engagement. That 'grab' also affects the LSD clutches. If you drive mostly in straight lines or do not get aggressive in your corner exits you will probably never detect the difference in LSD operation.

There was an anecdotal report on Prime of someone who went 100% with Red Line MTL and was getting lock up of the differential in aggressive cornering. Flushing the Red Line and replacement with with Honda MTF resolved the problem.

 

[Honcho]

Hello all!
With spring right around the corner I plan on un-mothballing my 96' NSX-T and change both the engine and manual transmission oils. I'm curious if anyone has any manual transmission gear oil preferences or if they just follow the service manual recommendation of an SF or SG API service grade in either a straight 30 weight or 20W40 weight (I live in the north east but it is strictly driven between spring and fall.

Does anyone have any thoughts or suggestions? All will be sincerely appreciated!


Matt

Unless the car is heavily tracked in hot weather, use the Honda MTF II (white cap). If you do drive the car on the circuit, you should change the fluid afterward. The Honda MTF does not like heat and will shear down very quickly after hard running at the track.

I will track my NSX, so I'm using Torco MTF and it is a little less notchy than the Honda fluid, especially at colder temps. It's closer in viscosity to the Honda MTF I and III, and it is shear stable under heat and load.

 

[Old Guy]

Unless the car is heavily tracked in hot weather, use the Honda MTF II (white cap). If you do drive the car on the circuit, you should change the fluid afterward. The Honda MTF does not like heat and will shear down very quickly after hard running at the track.

I will track my NSX, so I'm using Torco MTF and it is a little less notchy than the Honda fluid, especially at colder temps. It's closer in viscosity to the Honda MTF I and III, and it is shear stable under heat and load.

Now you have me curious.

Torco is a GL-5 gear oil. GL-5 oils are typically used with hypoid gears (think old school differentials). They usually achieve that GL-5 rating with lots of EP additives which are typically sulfur / phosphorous compounds. Everything that I have read says that these additives can react aggressively with copper / bronze which is bad news for synchro rings. Does the Torco use non sulfur / phosphorous additives or are the NSX synchro rings some other material?

 

[Honcho]

Now you have me curious.

Torco is a GL-5 gear oil. GL-5 oils are typically used with hypoid gears (think old school differentials). They usually achieve that GL-5 rating with lots of EP additives which are typically sulfur / phosphorous compounds. Everything that I have read says that these additives can react aggressively with copper / bronze which is bad news for synchro rings. Does the Torco use non sulfur / phosphorous additives or are the NSX synchro rings some other material?

Torco MTF is yellow metal safe- it scores a 2a on the ASTM D130 test. The NSX synchro rings are made from brass. Both the Torco RTF and MTF are designed for synchronous transmissions.

My differential is a bit noisier than with the Honda MTF, but it locks up within the spec for the NSX-R. It's really the only thing I notice that's "worse" with the Torco. I'm going to do a UOA after 500 miles to get an idea of wear.