Diff whine =\

[physicns]

So what I thought had been gear whine, I've since realized comes from the back of the car :( The noise has been getting slightly louder, and after reading countless threads on the 'other' forum (including many responses from Dave) I called the dealer and am taking it for a checkup at the dealer tomorrow morning.

I can only hear the noise at highway speeds with the top up. It's most prominent when the drivetrain is lightly loaded, and in gear. The sound is high-pitched and not altogether unpleasant, and sounds similar to what you'd expect from straight-cut gears, but very faint. For the longest time I thought it was a noise I should expect from a performance-oriented car like the S2000, but reading the forums gave me second thoughts.

I'll post an update after I get it checked out tomorrow. My car's a MY05, so the warranty will be up next year. I'm not sure what to hope for... the dealer to say 'oh it's normal,' or for them to go with a diff swap. From your responses on the other forum, Dave, I know I can't expect anyone to troubleshoot this over the forum, but I wanted to post it here just to raise a bit of concern with others who hear a similar whine, and thought it was normal (like me).

Cheers,
Ryan

[repiv]

A whine from the rear of the car can be the diff, wheel bearings and in some rare occasions, the prop shaft CV joint.
If it's the diff, you can put in a thicker diff fluid like the LE product or even a thicker multigrade synthetic. The pitch of the whine will most likely change or disappear.
If it's wheel bearings on one side or the other, run it up to the speed you normally hear it and find curves that will load up each side. Loading or unloading a bad wheel bearing will also change its pitch.
A bum prop shaft CV will show up upon physical inspection.

For an '05, it's less likely to be wheel bearings or prop shaft CV, but not impossible. This leaves a higher probability of it being the diff. Have you had the fluid changed? By whom? With what?

[physicns]

I haven't changed the fluid yet--it only has 7500 miles on it. I purchased it used in the spring with ~1600 miles, so I haven't figured it necessary yet. It's not the whine that bothers me; I can live with it--what bothers me is the possibility of serious damage sometime down the line, esp. when the car will be out of warranty.

If the dealer hears it but doesn't want to do anything about it, I'll ask them at least to change the diff fluid today (I'll see what they say about the thicker oil).

Thanks!
Ryan

[s2kmugen]

i had the same issue on my 01 w/ less than 25k (after it was 5 years old). I didnt know it could have been my prop shaft for my CV joints or wheel bearings. good luck w/ the issue

[repiv]

I haven't changed the fluid yet--it only has 7500 miles on it. I purchased it used in the spring with ~1600 miles, so I haven't figured it necessary yet. It's not the whine that bothers me; I can live with it--what bothers me is the possibility of serious damage sometime down the line, esp. when the car will be out of warranty.

If the dealer hears it but doesn't want to do anything about it, I'll ask them at least to change the diff fluid today (I'll see what they say about the thicker oil).

Thanks!
Ryan

Many (myself included) believe the very first diff fluid change should be done in the first couple thousand miles to get the break in crud out. With 7500, it's certainly not too early to do. Make sure your dealer knows that they must get the fluid from their motorcycle or marine division. If they use what they have "in house", you diff will be toast within a matter of days or weeks. (On second thought, maybe that would be a good thing. You can get them to give you a brand new diff. :p )

[physicns]

So I took it into the dealer this morning, and the tech definitely heard the ringing/whine. Turns out the sound is most audible at exactly 68MPH, under load. Some sort of resonance. They're keeping the car for a couple of days to see what's up. I'm going to wait for their call, and if they're going to pass it off as normal, I'll ask for a diff fluid change. Do you guys know what the part number for the S2000 OEM diff fluid is? I want to make sure they put the right fluid in, in any case. I'll bring up the LE1605 fluid, but I can't expect them to put in a fluid they're not familiar with.

Thanks again for the help!

P.S. S2kmugen--what did you eventually do? I'm assuming your diff isn't populating the roadside right now :p Like I said earlier, I'm more worried about potential problems down the line than just the noise itself.

[pezjunki]

I noticed the same thing. I had the diff fluid changed and it went away. It took a little while, but it did go away. Hopefully no permanent damage....

[physicns]

The dealer gave me a call and said they changed the diff fluid and the sound went away. The car's ready for me to pick up... I'll check it the part # of the diff fluid when I get it (not sure when yet... still have to figure out a way to get there ... lol). Hope everything's a-dandy.

[repiv]

Do you guys know what the part number for the S2000 OEM diff fluid is?
There is NO OEM rear diff fluid for an S2000. It will be a part number from their motorcycle or marine division. If they gave you an OEM part number, you've got the VTM-4 fluid they put into the diffs of CRVs and Pilots, etc. You will be getting a new diff shortly.

[ebeldesign]

I had the exact same diff whine you are describing and a fluid change with Amsoil stopped it. Incredible how sensitive these are to fluids...

[physicns]

The dealer ended up replacing the fluid with "1.5 QTS TRNFR CASE 80-90"

They said that this is the fluid the factory puts into the S2000. They also said the whine was gone, but it sounded exactly the same when I left the dealer. If the diff doesn't blow, I'll just take it as a free fluid change from the dealer, and change it myself with the LE1605 in a couple thousand miles, when I make my next oil change.

Hopefully this won't bite me in the foot later...

[repiv]

The dealer ended up replacing the fluid with "1.5 QTS TRNFR CASE 80-90"

They said that this is the fluid the factory puts into the S2000. They also said the whine was gone, but it sounded exactly the same when I left the dealer. If the diff doesn't blow, I'll just take it as a free fluid change from the dealer, and change it myself with the LE1605 in a couple thousand miles, when I make my next oil change.

Hopefully this won't bite me in the foot later...

DANGER, WILL ROBINSON, DANGER !!!!!!!!
This is exactly what I had feared. Your dealer knows absolutely NOTHING about this car. Transfer case fluid is likely that VTM-4 fluid I already warned you about. It is NOT meant for an S2000 and it is NOT what came from the factory. An SAE 90 fluid came from the factory and we CANNOT get this same fluid from Honda car division. Honda even issued a memo to their dealers about NOT using VTM-4 fluid. (Also, our rear diffs take 0.75 qts of fluid. You CANNOT get 1.5 qts into the casing unless you turn the car on its side.)

If it is indeed transfer case oil (or "dual pump" as they call it), your diff will NOT last a couple thousand miles. You will be lucky if damage isn't done after 100 miles. Oh, that P/N is the Canadian one, so may not be relevant to the US.

Here is the Canadian memo. I believe Honda USA has a similar memo.
http://forums.s2kca.com/photopost/data/15353/medium/diff_fluid.JPG

Click here (and scroll down) for the bigger readable version:
http://forums.s2kca.com/photopost/showphoto.php?photo=19471&size=big&cat=

[nytehawk]

I'm a bit concerned about this issue as well, since it seems like many dealers aren't up to speed on what fluid is supposed to be used. (My '07 S2K has a bit under 1500 miles on it and I'm planning to have the diff fluid changed by the dealer at ~3000 miles with first oil change.)

Should I just buy some Mobil 1 75W90 as suggested in the http://forums.s2kca.com/showthread.php?t=19891 thread and tell the dealer to use that instead of whatever they think it might need?

[repiv]

I'm a bit concerned about this issue as well, since it seems like many dealers aren't up to speed on what fluid is supposed to be used. (My '07 S2K has a bit under 1500 miles on it and I'm planning to have the diff fluid changed by the dealer at ~3000 miles with first oil change.)

Should I just buy some Mobil 1 75W90 as suggested in the http://forums.s2kca.com/showthread.php?t=19891 thread and tell the dealer to use that instead of whatever they think it might need?
You certainly can't go wrong (mechanically speaking) going with the Mobil 1, but if you are a conscientious owner who may have some concerns about warranty (not that you should) or what the dealer may think (not that you should), I suggest you go to your nearest Honda motorcycle shop and buy a bottle of the hypoid gear oil that is stated in my posted memo. That way, your dealer can put it in and use the Honda recommended fluid. You are then completely covered (not that you wouldn't be had you done it yourself using M1).

[thereur]

As far as warranty: we all know that LE607 and LE1605 are roughly similar weigh oils. However, the LE1605 does say "SAE 110" on the bottle (SAE standards have changed). I would never tell a dealer I had LE1605 in the diff. TMI I'll just tell them it's LE607 ("SAE 90" on the bottle).

[physicns]

Hey guys,

I called the service and parts department, and they clarified that the '80-90 Transfer Case fluid' is indeed Mobil 1 80-90 oil, and that it's used ONLY for the S2000. When I kept asking, the parts guy was kind enough to clarify that other the other Hondas use different fluids such as the VTM or dual-pump, just to clarify. So I feel a lot better about it. I think I'll get some LE fluid from Rick's, but I don't access to the tools to change it for a while.

I asked them where they source the diff fluid, and they say they just buy it in bulk,

This is a relief, right? I hope my car is safe to drive now! :p
Ryan

[repiv]

Hey guys,

I called the service and parts department, and they clarified that the '80-90 Transfer Case fluid' is indeed Mobil 1 80-90 oil, and that it's used ONLY for the S2000. When I kept asking, the parts guy was kind enough to clarify that other the other Hondas use different fluids such as the VTM or dual-pump, just to clarify. So I feel a lot better about it. I think I'll get some LE fluid from Rick's, but I don't access to the tools to change it for a while.

I asked them where they source the diff fluid, and they say they just buy it in bulk,

This is a relief, right? I hope my car is safe to drive now! :p
Ryan

Yes, it's safe to drive IF what they say is true. Here is the only 80W90 gear lube that Mobil makes. It's not exactly "Mobil 1" but rather "Mobilube HD". The fact that they called it "transfer case fluid" still means they really don't know what they're talking about. Luckily, they appeared to use the correct fluid. It's just too bad they aren't better informed so they can tell the customer exactly what's going on. Had they done this from the beginning, a lot of this fear mongering could have been bypassed.

http://www.mobiloil.com/USA-English/MotorOil/Other_Products/Mobilube_HD_Plus_80W-90.aspx

To back track, here is what they originally told you:
The dealer ended up replacing the fluid with "1.5 QTS TRNFR CASE 80-90"
This is TOTALLY inaccurate! Not only by name but wrong information about volume.

They said that this is the fluid the factory puts into the S2000.
This is painfully obvious that it's a BARE-ASSED lie.

[physicns]

Dave,

Thanks for the clarification of what's going on. I'm starting to realize that this is one of the serious drawbacks of owning a unique car, when Honda is used to sales volumes over an order of magnitude higher.

The parts guy said the 'transfer case' is the housing for the differential. I wasn't clear on this so I didn't push it further.

Looks like I'll be buying a jack and a few jackstands in the near future!

Thanks again Dave & others, this was extremely helpful! :thumbup:
Ryan