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2005 GT 4.6 rattling/knocking noise when turning/accelerating

2814 Views 10 Replies 6 Participants Last post by  S197_2020
Hi community,

I finally decided to open up a new thread to make use of everybody's knowledge, advise and experiences. I already read trough Dingo7222's thread which sounded exactly like the problem I have with my car. But, I checked the motor mounts and especially the spacing of the steering shaft and came to the conclusion that my problem is different from his.

Repairs that have been recently done:

- Lower ball joints
- inner tie rod ends
- outter tie rod ends
- sway bar links
- both front strut assemblies

After replacing all these parts, the noise is still there but it improved slightly. Especially when I'm turning right and accelerating there is a rattling/knocking and grinding noise. Also when accelerating from a full stop or driving on a bumpy road the noise will come up. You can definitely feel the vibrations. Surprisingly, during left turns the sound disappears. I jumped into the passenger seat today and could feel the knocking/grinding/vibrations under my left foot, pretty close to the middle console in about the left center portion.

The intensity increases when taking longer drives and the car heats up. What I also felt was a drop in power when I shift from the 4th to 5th gear, I don't know if this is also related to the issue. When I pull it out of my garage and go to work, (3 miles one way) everything is fine and I can barely feel it.

Does anybody have a clue what it could be? Maybe something with the drivetrain? (shaft)

I really want to get this fixed as its really annoying and driving me crazy.

Thanks in advance!:grin:

*EDIT: Just took it for another drive. After the car and parts warmed up, when accelerating slowly out of a full stop there is a grinding noise in the section mentioned above, accompanied by little resistance until picking up some speed. It might be a driveshaft bearing, that is something that I am guessing right now.
1 - 11 of 11 Posts
Hi community,

I finally decided to open up a new thread to make use of everybody's knowledge, advise and experiences. I already read trough Dingo7222's thread which sounded exactly like the problem I have with my car. But, I checked the motor mounts and especially the spacing of the steering shaft and came to the conclusion that my problem is different from his.

Repairs that have been recently done:

- Lower ball joints
- inner tie rod ends
- outter tie rod ends
- sway bar links
- both front strut assemblies

After replacing all these parts, the noise is still there but it improved slightly. Especially when I'm turning right and accelerating there is a rattling/knocking and grinding noise. Also when accelerating from a full stop or driving on a bumpy road the noise will come up. You can definitely feel the vibrations. Surprisingly, during left turns the sound disappears. I jumped into the passenger seat today and could feel the knocking/grinding/vibrations under my left foot, pretty close to the middle console in about the left center portion.

The intensity increases when taking longer drives and the car heats up. What I also felt was a drop in power when I shift from the 4th to 5th gear, I don't know if this is also related to the issue. When I pull it out of my garage and go to work, (3 miles one way) everything is fine and I can barely feel it.

Does anybody have a clue what it could be? Maybe something with the drivetrain? (shaft)

I really want to get this fixed as its really annoying and driving me crazy.

Thanks in advance!:grin:

*EDIT: Just took it for another drive. After the car and parts warmed up, when accelerating slowly out of a full stop there is a grinding noise in the section mentioned above, accompanied by little resistance until picking up some speed. It might be a driveshaft bearing, that is something that I am guessing right now.


I would check the sway bar bushing and control arm bushings
You said the problem disappears when you make a left turn, so does the problem become worse when you make a right turn?
I can't help wondering if the driver's side engine mount is shot.
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Thanks for the quick replies. I will swap the driveshaft next weekend and see if the problem gets solved. It has about 160.000 miles on the clock. I might order new motor mounts and change the old ones just in case.

I'll keep you updated. :grin:
I honestly don't see where a new drive shaft will solve anything. Save your money.
You might be on to something with your concerns about the bearings.
What's the history on the transmission. How old is the fluid.
As mentioned earlier, if the motor mounts and front end bushings are original, I'd replace those dried out, crumbling parts. Cost way less than a drive shaft.
I don't think bearings would make a knocking sound over bumps unless they are falling out but then you'd hear noise all the time. I agree that the drive shaft won't solve this issue. I'm sticking with sway bar and or control arm bushings. I'm leaning more to sway bar only because it happens while turning. While turning the weight shifts and bad or worn sway bar bushings will allow the bar to move and make noise
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Could be a bad wheel hub bearing. When my passenger side hub bearing began going out it made a grinding noise and would get worse turning the wheel one direction and less worse in the other.
Could be a bad wheel hub bearing. When my passenger side hub bearing began going out it made a grinding noise and would get worse turning the wheel one direction and less worse in the other.
Yes that's a possibility and in the OP's case, it would be the front driver's side.
Strangely I was about to suggest the driveshaft when I read the OP. I would not like to buy a new one, but I would try to find a way to isolate the issue and see if it could be the problem. If other people are not familiar with the drive shaft on this year, it is not a solid normal/typical driveshaft. (I am uncertain about later versions of the mustang) It was designed with a floating internal weight system which is supposed to help with vibrations/oscillations. I have not read anything about what happens when this design ages/fails. It is also a two piece design with added issues of the additional connection and dampeners. So while I would normally never think about a driveshaft causing noise, it was something that came to mind after eliminating the more typical areas.

I would think examining the car on a dyno may help, not that I would get near it in that situation.
Well I tried to knock the most common parts out. The vibrations and noise are coming from under the center console, gearbox is fine and all fluids have been changed last year. When driving over bumps the knocking does not show up immediately, it feels like its setting something right under the center portion (under my right foot when driving) of the car up to vibrate with a little delay. The clunking/vibrations are not coming from the front portion. What's interesting is that it increases when the car warms up. Motor mounts will definitely be changed as well. The driveshaft will be delivered tomorrow. I am curious if that will cure the issue.
So the driveshaft has been changed and I can tell there is a remarkable difference as far as smoothness and vibrations are concerned. The vibrations and the noise aren't fully gone but decreased by 80 %. Next things I want to change are motor mounts and the transmission mount. Any suggestions which mounts I should use?

I had another look at the sway bar and lower control arm bushings. The lower control arm ones looked pretty old and done. After the shaft was changed, I took it for a ride. I noticed that some minor vibrations and knocking sounds where coming up when turning right and also when accelerating hard from a full stop. As previously stated they are almost gone (still at the same spot), it's a huge improvement and the car is so quiet now and drives really smooth. Nearly as good as new.

Thanks for your help so far! I'm happy to get some more suggestions and advise! :grin:
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