Ive had a slight whine from diff. its probabyl been like it for as long as i had the car but I now just started to pay attention to it after reading about all the diff failures on here. Its audible but not loud at all at around 70-80mph. the whine changes on different pavement types, on nice smooth pavement the whine is barely audible, on older pavement its audible. My diff fluid has always been changed ever 10k with mobile 1 or amsoil....should i be concerned?

 

I think it's normal, especially when you are lightly using the gas pedal at those speeds. When you let off on the gas is when you will occasionally hear a little bit of whining. You have to remember that you will hear every noise going on with this car when the top is up and the radio is off. You might as well learn to like all of those noises, or get a louder radio!
Also, when you change the diff oil next time, take a mid-stream sample and send it in to Blackstone labs for an analysis. That will give you peace of mind.

 

mine does the same thing. i put some royal purple GL6 in the diff rather than the GL5 that honda recomends and it seemed to help. it also seems smoother

 

The official API GL-6 gear oil qualification is "inactive"
Do a search for "API GL-6" and you'll find enough documents that state it.
Here's a quote from one of them:
Found here:
http://www.lubrizol.com/AutomotiveGearOil/GL5.asp

This "high pinion offset" is explained here:
(note that it is a complete coincidence that they mention Richmond Gear )
http://www.truehi9.com/gears2.html

Honda states to use a single 90 weight oil for the diff, GL-5 or GL-6.
Reason enough for me to do so, after reading the websites mentioned above.
LE-607

And I agree with INDYMAC.
With an OEM diff I was surpriced the OP can isolate the diff "noise" at 80 mph.
I never could.
Not with an engine / gearbox / exhaust / softtop (and a diff ) surrounding me.

 

I also have a diff whine.I notice mine @ 42 mph on flat road with light load.If i accelerate the noise goes away.Also it seems to fade away @ 50 mph and then returns @ 65.It has done this for as long as i can remember.Diff fluid changes have made no difference and the old fluid always looks normal.The car has 35k on the odo and ive changed the fluid 3 times.Ive driven many other s2ks that do not make this noise.Who knows...maybe its how my backlash was set from ther factory.

 

i got my gl6 from an R/V place that has been in busniess since 1960 at 4 dollars a quart hey hooked it up

we know they dont call anything gl6 anymore but it is still out there on a shelf someplace

 

thanx for the reply fellas, not to mention i notice mine louder because i had removed some of the sound deadening as well as the plastic lid the soft top sits on, due to when i had a stereo system in there.

 

if i slightly press the accelerator when doing say 50mph i get a slight loose noise kind of like the prob shaft has a bit of play or something or a bearing is this normal or not sounds like its coming from the diff but im not sure?

 

I have this same niose it gets worse over time - i checked my driveshafts/cv's and it has a play think that could be the problem