NSX differential

[duncan]

If Honda specify a 10W30 or 10W40 'engine' oil, why would you put a 75/80 ,transmission' oil in?
The LSD for the pre 1995 M/T [5 speed] plus all years A/T compared to the 1995 on M/T [both 5 and 6 speeds] are very similar; the sun wheels are an enclosed set and are sandwiched between two clutch packs in the diff case, all lubricated by the gearbox oil. The later M/Ts have less plates/clutches in the sandwich but have in-lieu thrust races against the case itself. So whether the sun wheels have a 'torsen' style helical twist or not, the diff is relying on these 'wet' clutch packs to lock the diff.
My assumption being that as the diff spins the oil/ clutches heat and then lock, in a similar fashion to the steel on steel expansion of bellville washers in a Salisbury style 'Powr-Loc' LSD.
As Honda specify the gearbox and hence diff oil as 10/30 or 10W/40 'engine' oil, as opposed to [say] Castrol LS or B373, the plates/clutches have presumably been so engineered and optimised. A different grade or style of oil, or oil additives will surely alter the bite character of the diff.
So......10W30 or 10W40 SF or SG grade every 2 years......

[Silver Surfer]

If Honda specify a 10W30 or 10W40 'engine' oil, why would you put a 75/80 ,transmission' oil in?
The LSD for the pre 1995 M/T [5 speed] plus all years A/T compared to the 1995 on M/T [both 5 and 6 speeds] are very similar; the sun wheels are an enclosed set and are sandwiched between two clutch packs in the diff case, all lubricated by the gearbox oil. The later M/Ts have less plates/clutches in the sandwich but have in-lieu thrust races against the case itself. So whether the sun wheels have a 'torsen' style helical twist or not, the diff is relying on these 'wet' clutch packs to lock the diff.
My assumption being that as the diff spins the oil/ clutches heat and then lock, in a similar fashion to the steel on steel expansion of bellville washers in a Salisbury style 'Powr-Loc' LSD.
As Honda specify the gearbox and hence diff oil as 10/30 or 10W/40 'engine' oil, as opposed to [say] Castrol LS or B373, the plates/clutches have presumably been so engineered and optimised. A different grade or style of oil, or oil additives will surely alter the bite character of the diff.
So......10W30 or 10W40 SF or SG grade every 2 years......

SS

[NSX 2000]

SS

SS I think I might just second that.

Paul.

[NoelWatson]

If Honda specify a 10W30 or 10W40 'engine' oil, why would you put a 75/80 ,transmission' oil in?
The LSD for the pre 1995 M/T [5 speed] plus all years A/T compared to the 1995 on M/T [both 5 and 6 speeds] are very similar; the sun wheels are an enclosed set and are sandwiched between two clutch packs in the diff case, all lubricated by the gearbox oil. The later M/Ts have less plates/clutches in the sandwich but have in-lieu thrust races against the case itself. So whether the sun wheels have a 'torsen' style helical twist or not, the diff is relying on these 'wet' clutch packs to lock the diff.
My assumption being that as the diff spins the oil/ clutches heat and then lock, in a similar fashion to the steel on steel expansion of bellville washers in a Salisbury style 'Powr-Loc' LSD.
As Honda specify the gearbox and hence diff oil as 10/30 or 10W/40 'engine' oil, as opposed to [say] Castrol LS or B373, the plates/clutches have presumably been so engineered and optimised. A different grade or style of oil, or oil additives will surely alter the bite character of the diff.
So......10W30 or 10W40 SF or SG grade every 2 years......

"My assumption being that as the diff spins the oil/ clutches heat and then lock, in a similar fashion to the steel on steel expansion of bellville washers in a Salisbury style 'Powr-Loc' LSD. "

I don't think this is the case - the above to me sounds like a viscous coupling.

[duncan]

Definite answer anyone?;
if they were viscous then the discs could be paddles or vanes?, that they are clutches and plates made me think friction.
Whatever......the answer is MTF-3 or an equivalent?....
My final thought could you re-shim the clutch packs to a tighter assembly to either compensate for wear or to induce a more aggressive inital lock up?

[forumadmin]

Engine oil for the gearbox? Try it. Kowalski had it in his for a while and it made the car undriveable. The diff was locked solid.

Shimming and tightening up the diff is exactly what the Type R version is. Either the standard diff is loose, or after a while is not effective. I could spin an inside wheel at a track at will, with a trail of smoke behind me.

I have an OS Giken diff now. The spinning wheel syndrome has stopped but it is an odd drive on the road. It definately applies more lock as more power is applied (unlike the old diff). Halfway through a corner on the road, if I apply more throttle then the car straightens up. It's slightly worrying that its going to spit you into oncoming traffic on the other side of the road. At slow speed to get into parking spaces, or exits from junctions, it will have the car jumping as the clutch plates are forced to disengage. The amount of power that is now put to the road exiting bends on the track caused the clutch to start to slip. Everything has a side effect.

I thought just having both axles connected by a set of clutches just means there will be a small amount of torque applied to both wheels. Or, in other words if one wheel is in the air, the other will have the same amount of torque applied to it, the same as it takes to disengage the clutches. As the clutches take 100 lb/ft or so to break, then that amount of torque will always be applied.

[NoelWatson]

I'm pretty sure it's not a Torsen diff. Torsen diff are not usually fitted to RWD cars as they're better suited to FWD or 4WD cars.

I think the S2000 has a torsen (according to Wikipedia)

[Ewan]

... and http://corporate.honda.com/press/article.aspx?id=4096

[kowalski]

As Kevin mentioned, I had Engine Oil put in mine during a clutch change. The Diff seized up within a couple of days and the car was a nightmare to drive. It took 3 flushes of MTF3 to bring it back to normal.

The fault lay with the early service book which did say you could use Engine Oil, this was changed in later service book revisions.

Not recomended

leigh