91 Acura NSX Manual Transaxle Amsoil 5w30 14,000mi

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1991 Acura NSX manual transaxle. Uses a gear driven oil pump and has a mesh oil strainer. Holds 2.9 quarts.
I previously tried the current Honda MTF oil and was very unhappy with the shifting quality.
Honda recommended change interval is 20,000 miles. This oil felt great when first added, but shift quality was significantly deteriorated after 14,000 miles, which led to the early change. There are 4 track days on this oil.
The car has a slight gear whine type sounds at low speed that I suspect may be a transmission issue, maybe the input shaft bearing. Not sure if this analysis shows evidence of an issue or not.

NOTES FROM LAB:
Silicon appears to be slightly higher than normal. Have there been any recent repairs? Higher silicon concentration does not appear to have affected wear. Other readings appear to be normal.

Code:




ELEMENETS IN PARTS PER MILLION



Sample Date 10/31/16

Oil Amsoil

Synchromesh

5w30

Miles on oil 14,000

Total miles 121,067

Lab CAT



Notes Daily driven

in NV.

Several track

days.



ALUMINUM 9

CHROMIUM 1

IRON 39

COPPER 4

LEAD 7

TIN 0

MOLYBDENUM 0

NICKEL 0

MANGANESE X

SILVER 0

TITANIUM 0

POTASSIUM 1

BORON 3

SILICON 25

SODIUM 5

CALCIUM 313

MAGNESIUM 3561

PHOSPHORUS 1194

ZINC 941

BARIUM X





PROPERTIES





SUS Viscosity @ 210°F

cSt Viscosity @ 100°C 9.3

Flashpoint in °F

Fuel % 0.0

Antifreeze % 0.0

Water % 0.0

Insolubles % 0.3

Oxidation 74

Nitration 7

Sulfation 72

Particle Quantifying Index 7

ISO 22/18/14

4u 37420

6u 2068

10u 421

14u 142

18u 67

21u 46

38u 8

50u 3
 
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No pics of the car....
frown.gif
 
Originally Posted By: heynow
1991 Acura NSX manual transaxle.
The car has a slight gear whine type sounds at low speed that I suspect may be a transmission issue, maybe the input shaft bearing. Not sure if this analysis shows evidence of an issue or not.

Gear whine is an indication of inadequate gear oil operating viscosity and equipment abuse.

Assuming track days as part of the requirements and vehicle was not being abused, longevity of gear train components calls for gear oils of higher viscosity grade (in particular higher KV@40*C), mitigating increasing level of gear whines noise........
possibly at the expense of gearshift annoyance.

RL MTL/MT85/MT90 should be favorably considered ..... the thicker the better for components longevity.

JMHO.
blush.gif
 
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Originally Posted By: zeng
Originally Posted By: heynow
1991 Acura NSX manual transaxle.
The car has a slight gear whine type sounds at low speed that I suspect may be a transmission issue, maybe the input shaft bearing. Not sure if this analysis shows evidence of an issue or not.

Gear whine is an indication of inadequate gear oil operating viscosity and equipment abuse.

Assuming track days as part of the requirements and vehicle was not being abused, longevity of gear train components calls for gear oils of higher viscosity grade (in particular higher KV@40*C), mitigating increasing level of gear whines noise........
possibly at the expense of gearshift annoyance.

RL MTL/MT85/MT90 should be favorably considered ..... the thicker the better for components longevity.

JMHO.
blush.gif



I doubt the noise itself is actually the gears, I was really just trying to convey that it is a noise correlated to road speed and gear selection, hence why I referred to it as "gear whine TYPE sounds". I only get the sound in first gear, which is the gear I use the least (if at all other than to start from a stop) on track days, so I would assume it would be subjected to the least wear of all the gearsets. I also would think that the results of this analysis do not show the results of gear wear significant enough to cause audible detection.

Gearshift issues become much more than an "annoyance" when I am unable to even enter a gear during the first selection of the day, or for the fist 5 minutes during a winter day, not to mention relatively frequent grinding, all of which were experienced when using redline MT90.
 
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Honda has a tsb to use AC Delco Friction Modified MTF in the Accord V6 manual for a 3rd gear crunch/grind issue. Reports have been good after using it. Try some of that and make sure to get the FM stuff. Redline seems to get so-so reviews.
 
Originally Posted By: SatinSilver
Honda has a tsb to use AC Delco Friction Modified MTF in the Accord V6 manual for a 3rd gear crunch/grind issue. Reports have been good after using it. Try some of that and make sure to get the FM stuff. Redline seems to get so-so reviews.


That would probably hurt the function of the LSD, FWIW.
 
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