2021 Mach 1 - 1200 miles - clunk when taking off (Sometimes......)

[wiedemab]

It doesn't do it every time, but once it starts, it seems to continue for the remainder of that drive. From a dead stop, easy take-off there is a clunk/thud noise from the rear. I've had it up on a lift, checked the diff mount bolts, rear subframe bolts, driveshaft bolts, springs are seated properly, shock bolts are tight etc........ Any thoughts? No vibrations, no instability.

My latest thought is something to do with the carrier bearing, which I can't really see due to the resonator. I may try to mount my GoPro under the car in some various locations to see if I can see what is moving... Hell, I haven't even started to rip on the car yet.. :(

Thanks in advance for any thoughts

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[NGOT8R]

Is it a really loud clunk?

 

[wiedemab]

Is it a really loud clunk?

Not sure I'd say really loud, but you can definitely hear it inside the car.

 

[wiedemab]

I know I can take it to the dealer under warranty, but I've not had great luck in the past with their troubleshooting abilities on other vehicles - they just start throwing parts at it and hope for the best.....

 

[wiedemab]

Just went out to my driveway and backed up and pulled it forward a few times. If I let it roll back and pull forward it doesn't seem to do it. If I put it in reverse, back up and then back to 1st and pull forward it does. You can hear it in the vids at the link below - you can hear me move the shifter when I back up for reference.

https://photos.app.goo.gl/kL5gQyk8RAXrjX6AA

 

[mldonovan82]

Do you have anyone who can listen to where it’s coming from as you pull forward? It’s happening at such low speeds, I wonder if someone can isolate the sound…

 

[NGOT8R]

Could it be the normal sound of drivetrain backlash that you’re hearing?

 

[wiedemab]

My dad stopped out and listened... I think it may be PS axle... Some Google searching now has me thinking about axle nut coming loose. Busy on another project right now on the lift, but when I have time I'll check that. I had him back up and pull up and it does sound like PS something....

 

[wiedemab]

Could it be the normal sound of drivetrain backlash that you’re hearing?

No... I'm familiar with that.... It kinda sounds like what a broken u-joint sounds like...

 

[traxiii]

No... I'm familiar with that.... It kinda sounds like what a broken u-joint sounds like...

No vibration when driving after it make the noise?

 

[wiedemab]

No vibration when driving after it make the noise?

Nope, cruises down the interstate at 85 smooth as can be.

Going to check the axle nuts this weekend. I'll report back what I find. Based on what dad and I heard it seems more isolated to the PS.

 

[wiedemab]

Checked the axle nut and it's good... Talked to an old friend this afternoon that is a service manager at a Ford Dealer and he thought maybe it could be the wheel bearing - said they had a similar issue on a GT350 - could feel any play in the bearing, but something internally was messed up. I'll probably it take it to his dealer and let them figure it out. He'll make sure it's handled properly. I'll report back

 

[wiedemab]

No real update - haven't touched it since all of the checks that I did last week. Headed to the dealer on Monday to see what they can figure out.

I'm not going to lie, a bit pissed about having issues with the car this early and haven't even had it to a track day yet. - I bought this car to have fun with since my other projects are still being built. I wanted something I could jump in, have fun and not have to worry about working on all the time...... that's working out great so far... :(

 

[Cobrajet70]

The Mag ride will make some clunking noises at slow speeds, Like coming to a stop or just starting to move, Also wider tired mustangs will sometimes cause enough flex to the front subframe to cause a slight audial noise. These are considered normal.

 

[8GTOKLR]

Ford should get it sorted. Sounds like hub, diff..Its a rotational thud, the noise is rear central

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