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My Acura has recently developed a bit of a throaty ‘growl’ right around 3500RPM. It sounds like it’s coming from directly underneath the stickshift. I recently had the 1st and 3rd gear synchros and sliders replaced, as well as a new clutch installed. Would this cause the growl or could it be an exhaust issue?
Thanks!
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No not a grinding, the tranny was just rebuilt and it works flawlessly. It’s more of a throaty sound, similar to the sound of a high-power muffler, but I only hear it when the car is around 3500RPM. It actually sounds kind of badass (lol) but I know it wasn’t always there, hence why I am concerned.
I brought the car to my mechanic this morning to get the front brakes done, I told him to have a look.
ok I understand now.The video I posted still stands.
you may either have a hole in the exhaust of the muffler
has lost some of the internals. the video should help pin
point the problemI’d be checking one of these 2 things. In order to get the transmission out you need to drop the exhaust. It’s possible that the doughnut gasket that goes to the manifold has been compromised and it causing the noise. For this a good visual inspection might do the trick and since it was just out of there it shouldn’t be too hard to get to. The other thing to check is the intermediate shaft bearing heat shield. The axle also has to be removed and if this shield gets bumped around it can cause a noise similar to what you describe. You might try removing it to see if the noise is still there if it is perhaps you can reinstall it an reposition it so that it no longer makes noise.
Thanks Eric. I had the front brakes done yesterday so while there I told my mechanic about the noise. He said he inspected the exhaust system while the car was up on the lift and everything looked fine. We even went for a drive together and I pointed out the sound but he didn’t think it sounded abnormal.
Can I check the heat shield you mentioned without jacking up the car? I’m not familiar with this part…
While driving this morning I really tried to narrow this down in terms of when/what causes the sound and I noticed that it is much more pronounced when I’m upshifting while slowing down (causing the engine to rev into higher RPM’s). I can hear it when accelerating too but it’s not as obvious. If I put the car in neutral and just rev the engine I don’t hear the sound at all.
As I stated initially, I have recently had some tranny work done…could it just be that the tranny sounds different now that it has new synchros and sliders?
Thanks again!
You shouldn’t hear the transmission at all. Make sure they used Honda fluid though, that could be trouble if they didn’t. You can also use GM Syncromesh, it actually works pretty good in Hondas.
You’ll have to jack up the vehicle, it’s the heat shield on the right axle that you’re looking at. You can’t miss it, it covers the middle bearing on the right axle.
You shouldn’t hear the transmission at all. Make sure they used Honda fluid though, that could be trouble if they didn’t. You can also use GM Syncromesh, it actually works pretty good in Hondas.
You’ll have to jack up the vehicle, it’s the heat shield on the right axle that you’re looking at. You can’t miss it, it covers the middle bearing on the right axle.
I believe I’ve found the culprit! The exhaust manifold head shield is rusting out and the bottom two fasteners are no longer holding it in place so it’s rattling.
I’d like to replace it myself, but those bolts are very rusty and I’m afraid I’m going to run into problems getting them off. I’ve read about using penetrating oil or a torch to heat them up, but what if I end up breaking one? I’ll be screwed and end up having to take it to a garage anyways….
Thoughts?
I believe I’ve found the culprit! The exhaust manifold head shield is rusting out and the bottom two fasteners are no longer holding it in place so it’s rattling.
I’d like to replace it myself, but those bolts are very rusty and I’m afraid I’m going to run into problems getting them off. I’ve read about using penetrating oil or a torch to heat them up, but what if I end up breaking one? I’ll be screwed and end up having to take it to a garage anyways….
Thoughts?
Glad that you found the noise.can you put a
clamp on it to secure it? unless someone can
Tack weld the shield back. here is a link for
a heat wrap option.Glad that you found the noise.can you put a
clamp on it to secure it? unless someone can
Tack weld the shield back. here is a link for
a heat wrap option.Hi Eric, thanks for the response. I did come across this video the other day. The heat shield in question doesn’t really have the right shape to take a pipe clamp; it’s got a wide tapered shape so a clamp would probably slide off. I might try it just for the hell of it though since it’s such an easy fix. 😉
In the event that this DOESN’T work, any advice on removing those incredibly rusted bolts? I don’t have access to a torch or a pneumatic wrench/impact driver, and several of the bolts are deeply positioned near the engine where I wouldn’t be able to use your trick with a hammer. I’m just afraid I’m gonna break one of those bolts and will be unable to install a new heat shield. I’ve read that the exhaust manifold can also be wrapped in a special material? Perhaps this could be an option once I remove the shield?
Thanks again for your help!!!
Hi Eric, thanks for the response. I did come across this video the other day. The heat shield in question doesn’t really have the right shape to take a pipe clamp; it’s got a wide tapered shape so a clamp would probably slide off. I might try it just for the hell of it though since it’s such an easy fix. 😉
In the event that this DOESN’T work, any advice on removing those incredibly rusted bolts? I don’t have access to a torch or a pneumatic wrench/impact driver, and several of the bolts are deeply positioned near the engine where I wouldn’t be able to use your trick with a hammer. I’m just afraid I’m gonna break one of those bolts and will be unable to install a new heat shield. I’ve read that the exhaust manifold can also be wrapped in a special material? Perhaps this could be an option once I remove the shield?
Thanks again for your help!!!
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