Hey guys,

My Accord started making this "airplane" sounding noise at speed.
It shifts fine in all gears. I mean it has 150k and clutch disc and pressure plate are the original, so not perfect, but ok, no slipping that I can tell.

When I accelerate I don't hear the noise until I get up to 35-40 MPH and higher, but when I slow down after I get up to those speeds, I can hear it all the way to zero until the car stops moving. Engaging or disengaging the clutch has no effect on the noise, meaning it's probably not the gears, it's there when coasting in neutral.

At first, I thought it was the driveaxles, because the boots were cracked and a lot of grease flew out of there. I added some grease in and patched those but the noise remained.
I decided to go to the dealer to have it checked and they said it's from the transmission. The dealer said they would rebuild it and replace what is usually replaced in a rebuild and they would open it up and see if there's anything more needed it would add to that work. So, I'm not sure what exactly is bad inside the transmission, but I did ask, because it makes the sound in neutral, are they sure that's the problem? They said yes, because it spins even without the gears engaged. Also, they said that depending on, or for how long it made the noise, it can be fixed and something about rubbing or grinding in/at the case.

Of course the prices quoted are pretty high and I would want to fix it myself if possible. I can and have the capability to remove the transmission and replace it, but I checked prices for a rebuilt one (for example $1200 at autozone) and that seems high for me. This is partly because I would need to change a lot of other things (driveaxles, clutch disc, etc.) if I do this and it would add up.

I tried to research the issue online and forums, I'm not really sure what is wrong or what would need to be fixed inside the transmission. Maybe something like the mainshaft/bearing?

Other things to ponder:
At about 100K there was a engine vibration that turned out to be the front engine mount. It was pretty badly gone by the time it was replaced that the engine was leaning so much that the one of the radiator fans blade was close enough to something that it touched a little bit and made a bit of noise.
I wonder if this could be related. The dealer saw the issue back then, did not say anything about the other mounts, so I'm not sure.
So, I'm open to suggestions, for example let's assume the mounts have something to do with it, then, what could be the problem? How do I check?

Also, I'm sure the transmission fluid needs to be replaced, but I doubt it would cause this issue, right? Would not enough fluid cause some problems? (not saying it has low fluid, I'm just wondering).

If you have suggestions, if possible to also let me know for how long I can keep driving with this problem or what can happen if I keep driving. The car is at my sister and I want to bring it home to work on it, a 400 mile drive on the highway.

 

Help please.

 

the first thing you should do is drain and refill the trans fluid.

I am quite surprised that you have not done that already.

 

It is easy to do with a funnel and 3 feet of 1/2" diameter clear tubing.

It takes a 17 mm wrench to remove the fill plug and just a 3/8" socket driver to remove the drain plug.

Access them from the passenger side wheel, wheel does not need to be removed.

 

I can do it if you think that would help. It's just that I'm not home, I'm at my sister like I said and was wondering if I could drive it this way.

 

I would not drive it.

 

Changing the transmission fluid is not much harder than changing the oil on a car. Your car can take SF or SG Grade that is SAE 10W-30 viscosity. The "hardest" part is refilling the transmission.

It is very rare for a manual transmission to fail on a Honda, but it does occasionally happen. I would feel comfortable buying a used manual transmission from a junkyard. Search car-part.com for a transmission. You can sort by price or distance. If you are going to change the manual transmission, then you are basically a few steps away from replacing the clutch.

I wouldn't rule out the CV joints. You repacked the boots with grease, but the internals may be damaged due to lack of grease.

I would get a second opinion from a different shop.

 

Could be a bad wheel bearing. My left rear went bad and sounded like you describe. I got away with driving it for a week or so, but you don't want to push your luck. It seems to gradually get louder as the days go by. You can usually tell if the noise is coming from the back or front, but to isolate to the correct wheel hub can be tough unless a mechanic has it on a lift and can test them.