How to know if input shaft bearing is going?

I've had the same in-gear coasting noise since I got this transmission. It's an 06 si 6 speed in an RSX case. I just assumed the transmissions for the k-series were a little loud, since I remember the 5 speed from the EP3 being a little loud in gear and coasting as well. Anyway, I don't hear a noise idling with the clutch in or out, I only hear a sort of soft noise, sort of like a deep "sssshhhh" noise if I had to describe it. Google search always says "Input shaft bearing grinding" but I wouldn't say it sounds like grinding.

It only happens when in gear, and only really noticeable in 3-5th gear. It is loudest when I'm completely off throttle and coasting, loudest in 5th gear. I'd only notice it if the radio is completely off. I tried to record a video, but the audio sucks.

Just for funsies check the fluid level in the tranny. Won't hurt to check. Also verify the axles are fully seated.
If the gear box has a helical differential that may account for the noise. I noticed a similar sound coming out the pumpkin of my 240 when I replaced the worn out Kaaz with an S15 helical. Sounded like a whirring, hissing sound. Switching from dino to synthetic gear oil actually made it a bit louder at low speed but quieter at highway speeds.

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Originally Posted by tinman5

Just for funsies check the fluid level in the tranny. Won't hurt to check. Also verify the axles are fully seated.
If the gear box has a helical differential that may account for the noise. I noticed a similar sound coming out the pumpkin of my 240 when I replaced the worn out Kaaz with an S15 helical. Sounded like a whirring, hissing sound. Switching from dino to synthetic gear oil actually made it a bit louder at low speed but quieter at highway speeds.

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I was wondering if the differential might be the source...How do we "check" transmission fluid level? All I've ever done is fill and drain the thing the two times it's been out of the engine.

Lol. I know what you mean. Remove the upper plug and do one of 2 things 1) stick your finger in there, 2) assuming tranny juice does not bleed out, a good indicator there may be too much fluid, add a little bit of fluid via the speed sensor hole on the top of the tranny case. Its not an exact science unfortunately but add fluid until it starts leaking out the upper plug hole. Once she starts bleeding give the plug a couple wraps of teflon tape and snug her up. Not too tight, I think its something like 19 ft/lbs.
After I re-installed my tranny I topped her off with just under 2 quarts of Syncro Mesh. I rechecked the level after about 1000 miles and she took almost a cup more. Then I checked the level one last time at the following oil change almost 4k miles later and she took another ounce or so.
Its been over a year and I have no visible leakage but will probably check the level again on my next oil change. Wouldn't surprise me if she took another sip of juice.

And yes, if you are not used to it, the sounds coming from a helical are a bit unnerving. I genuinely believed I was destroying my 3rd member. I was assured by a friend the whirring sound was normal. It was not as loud as I thought it to be, but I had spent so much time with the car I literally knew the source of every creak, every knock every hiss and pop. The new noise stood out to me. Kinda like when you move into a new house, your ninja skills are on high alert until they weed out normal noises from zombies coming out the basement.

heh, yea, that's almost exactly what I'm going through. I've been experiencing the noise for over a year, but now that I'm worried it's a problem, it's all I hear, I can't tell if it's getting louder or staying the same!

If after a year nothing has broken off, exploded, caught fire or gotten any worse/louder I would think it is in fact the helical just keepin' it real.
I will be installing one myself here soon as I can find one, preferably dirt cheap. The fact I have gone this long without one is kind of stupid on my part.
But hey, thats how I roll...

I really hope that's the case. I don't drive the thing hard, hoped that would pay off. Might get a shops opinion, and I'll listen to see if it's getting louder.

Consider switching to a different type/brand of tranny juice. That may help. If ultimately you feel the gear box has to come down, well I can think of much worse ways to spend a day. It would suck, but ones confidence in the machine is every bit as important as ones skill using the machine.
Good luck either way. Too bad you're not closer, I'll bust out the floor jack, stands and sheet of cardboard at the drop of a dime.

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Originally Posted by tinman5

Good luck either way. Too bad you're not closer, I'll bust out the floor jack, stands and sheet of cardboard at the drop of a dime.

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That would be awesome. I know another ephatcher that'd do that, but he's down in CT, and arranging time that works for both of us isn't easy.

Guy I play racquetball said the same thing...if it's been running this long and hasn't caused a problem, just don't worry about it. I'll listen to it every now and then to see if it's gotten worse, might have Autofair check it out this weekend, but otherwise, going to just roll with it.

edit- I got paranoid again and started searching for causes...maybe the LSD bearing could have gone bad?

All depends on the install.
If it was a simple case swap, which should honestly only involve the bell, nothing should have been dissassembled. Now if it was a complete tear down with new bearings pressed on...I have confidence that even a half blind monkey could tell the bearings were not seated correctly. Its not impossible, just some degree of ignorance or intentional malice would preclude the installer from noticing.
That particular bearing/race configuration is very stout. You would grenade the gearbox before affecting the side bearings.
I feel at this point you should have the car inspected by a reputable shop. Have the fluid drained and screened. Aside from the usual glitter, there would have to be some noticeable additional slur present in the fluid.
Get you some piece of mind brother.

So the clutch case wouldn't have been changed? it'd just be the bell housing? Didn't realize that. Is the VIN on the bell housing or the clutch case?

Autofair said the noise is backlash. Tech seemed really knowledgeable in regards to transmissions. Glad I went. Still had them change the transmission fluid to make sure the level was correct. They checked the car over too. Happy with the piece of mind.

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Originally Posted by ryboto

So the clutch case wouldn't have been changed? it'd just be the bell housing? Didn't realize that. Is the VIN on the bell housing or the clutch case?

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It all depends on what exactly was needed done. For example, I cracked my clutch case. I was able to find a 5 speed tranny for sale locally and cheap. I split the cases and literally swapped out all the guts (as my gearbox is a 6speed) and reassembled the case. The vin is on the bell if memory serves.
Now, if I were to do a swap with an lsd tranny, I would use my bell on the helical clutch case. This to be able to use the EP's speedometer gear. Instead of having to run a converter or drill out the hole to install the speedometer drive.
Lastly, I'm glad you got the car checked out. Now go find you some nice mid-speed "esses" with a hairpin or two and late brake in and power out like you mean it.