Vibrating/Click Sound from Rear Under Hard Acceleration

T

TheMole

Member
Car
2004 FX35 RWD Base
Name
Mo
Hey all, just picked up a 2004 FX35 rwd base model and am noticing this vibration/clicking sound when accelerating hard. From what I've read it looks like the rear axle needs to be greased. Just want to confirm if this is what it should sound like or can it be something else. Other than this sound, the car seems to drive fine.

There is an aftermarket exhaust installed that has a portion of the pipe sitting really close to the diff housing, but I didn't see any signs of contact on the piping. Also the rear diff/subframe donut bushing looks to have spilled its guts, but doesn't look like it would make that noise.

Here is a vid I posted on youtube. Kinda hard to hear with the exhaust sounds, but it can be heard around the 4 second mark.

 
Thanks guys I'll crawl under the car and check as soon as it stops raining over here.
 
UPDATE:

Finally had a chance to crawl further under the car to inspect and it looks like the passenger side exhaust pipe is super close to the diff ear mounting bolt on that side. Also noticed a heatshield in the rear was bent up to make room for the exhaust piping so it sits close to the driveshaft joint. These 2 things might explain why I only hear sound under heavy load. Looks like the muffler shop could have easily cut and adjusted that section of pipe for more clearance, but the catback came with the car so can't complain. I was looking to trade for an oem catback anyways so I think I'll just leave it for now.

Here are a few pics and a clip of how the exhaust sounds without the currently installed silencers. Revving starts around the 01:15 mark.

20190220_133647.jpg 20190220_133653.jpg
 
Another Update: Looks like it could have been my motor mounts all along. Checkout how much the engine moves while I was power braking the car. I'm assuming this isn't normal? I can also replicate the vibrating sound if I rev it higher while doing this. Sorry couldn't get a full shot of the engine bay, but my camera guy is on vacation so had to this by myself.

Just changed out the valve covers, gaskets, and spark plugs so not really looking forward to this haha. I read the DIY and the left side mount doesn't seem too bad with some special tools, but what about the passenger side? Looks like the exhaust manifold might have to come off. Transmission mount seems pretty straight forward once the y-pipe is removed.

 
TheMole said:
Another Update: Looks like it could have been my motor mounts all along. Checkout how much the engine moves while I was power braking the car. I'm assuming this isn't normal? I can also replicate the vibrating sound if I rev it higher while doing this. Sorry couldn't get a full shot of the engine bay, but my camera guy is on vacation so had to this by myself.

Just changed out the valve covers, gaskets, and spark plugs so not really looking forward to this haha. I read the DIY and the left side mount doesn't seem too bad with some special tools, but what about the passenger side? Looks like the exhaust manifold might have to come off. Transmission mount seems pretty straight forward once the y-pipe is removed.

Click to expand...
Deeeyaaaaaaaaaaaaaaaammmm! That's nutz.
 
TheMole said:
UPDATE:

Finally had a chance to crawl further under the car to inspect and it looks like the passenger side exhaust pipe is super close to the diff ear mounting bolt on that side. Also noticed a heatshield in the rear was bent up to make room for the exhaust piping so it sits close to the driveshaft joint. These 2 things might explain why I only hear sound under heavy load. Looks like the muffler shop could have easily cut and adjusted that section of pipe for more clearance, but the catback came with the car so can't complain. I was looking to trade for an oem catback anyways so I think I'll just leave it for now.

Here are a few pics and a clip of how the exhaust sounds without the currently installed silencers. Revving starts around the 01:15 mark.

View attachment 602902 View attachment 602903
Click to expand...
That sounds good. :tup:
 
From the looks of the video it seems as though your left side (drivers side) is the problem. It's either loose or broken. I think you can probably just replace the one for now and see if it rectifies the situation.
 
IlovemyFX said:
From the looks of the video it seems as though your left side (drivers side) is the problem. It's either loose or broken. I think you can probably just replace the one for now and see if it rectifies the situation.
Click to expand...

Thanks I think thats what I'll do.

Had a chance to take the drivers side wheel off and I think it looks a little broken don't you think? :LOL:

Raised the engine a bit and look at that gap!
20190314_161706.jpg

This powerbraking vid explains it all.
 
You might consider replacing the engine and transmission mounts. The rest can't be too far behind.
 
onthemove said:
You might consider replacing the engine and transmission mounts. The rest can't be too far behind.
Click to expand...

Definitely will look into them once I get this one replaced. Do the transmission mounts usually go bad on these cars? I'll remove the bracket that hides the mount the next time I get a chance to crawl under there.

Edit: Current mileage is 154k
 
I've had 0 problems with mounts but did have a differential bushing fail on me last year.
A mount as bad as yours is allowing for greater force to be exerted on the rest of'em. I guess it depends on how long this has been an issue for your FX and if there's a known defect with these motors mounts. You're in Southern California where it's dry (dry rot) and the age and mileage don't help. If the FX is a keeper, replace'em and if not, screw it. :tup:
 
Finally had a chance to change out the motor mount and glad to report back that the sound is now gone! Changing the mount wasn't bad at all as I went through the driver's side wheel well and used a 14mm flexible ratchet wrench for the top nut. It's kind of an awkward position so I held the wrench down on the top mount nut with one hand to make sure it was snug and tapped the other end of the wrench a few times with a rubber mallet to get it loose. It is very close to the exhaust manifold so I recommend working on a cool engine. The rest of the process with removing the bottom 17mm nut and supporting the motor with a jack is straightforward.

Some pics below:

Arsenal
20190321_165025.jpg

Method
20190321_165001.jpg

Old broken mount (that dried fluid is epoxy from a past failed attempt at fixing it)
20190321_173450.jpg

New mount installed
20190321_173506.jpg
 
Last edited:
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