When I start driving from 1st to 2nd to 3rd gear, i hear a whining noise. Is it the clutch or differentials? I have my00.

 

It's probably the owner ...

JUST KIDDING!
If the sound pitch is directly related to speed (increases in pitch as the car speed up) it's more than likely the rear end. Since it's an older car (I'm assuming you're not the original owner), I'd change all the fluids.

I'm a big fan of Amsoil synthetics, and Amsoil currently is the only aftermarket manufacturer of a direct Honda MTF replacement for the transmission.
A lot of folks (including myself in the past) have had success with GM Synchromesh Friction Modified (GMSMFM). The new Amsoil MTF is also a listed replacement for this fluid.
As for the diff, Amsoil Severe Gear 75W90 is a fantastic (and quiet) gear oil well suited for the S2000's diff. People will kick and scream on this forum stating that Honda calls for a straight 90 weight. Amsoil says their Severe Gear 75W90 is perfect for a hard driven S2000.

A lot of folks are big fans of LE607. I tried it and found little to no benefit of the LE. If you track your car regularly, I think there's a benefit (on warm track days). However, it's too thick for winter driving and impacted my highway mileage. Some folks have found it quiets noisy diffs though. However, this benefit lasted less than 2000 miles in my car.
Hope this helps.

 

Long story short.
I tried chainging my diff fluid,
drained and when I tried opening my fill bolt stripped the bolt,
so I filled as much as possible from the bottom bolt and the close (1/3 of quart)
I took to mechanic and told him what situation was.
he ended up driving the car maybe 80 miles.
when I got my S back it has a whining sound
do I need to replace my Diff?

 

"I took to mechanic and told him what situation was.
he ended up driving the car maybe 80 miles.
when I got my S back it has a whining sound
do I need to replace my Diff?"

I hope you know this mechanic? 80 Miles? Whining now?
May be time to chat with the service manager.

 

a friend mechanic that does side jobs.
was recommended by a fellow S2KI member
he wanted to take the car to a friends house 40 miles away to get second opinion on my tanny problem.
(it grinded going in to first) my 1st syncro is bad
but as a mechanic they should know not to drive a car that much with small amount of fluid

I found someone locally selling a diff for 300.00 now have to look for someone to replace it


but I did find the answer
https://www.s2ki.com/forums/index.php?showt...0&#entry9809098