Mysterious clunk.

[rorrerjp]

Im starting this thread to keep everything pertained to this together in one thread. This is the original thread Axle shaft problems? | 2015+ S550 Mustang Forum (GT, EcoBoost, GT350, GT500, Bullitt, Mach 1) - Mustang6G.com. It is similar to the clunk forum member "ShapeShifter"

I've had a clunk occurring with my car slowing down at around 17 and 3 mph (like coming to a redlight no variables/conditions changing). It also occurs from a stop when going F to R to F. Basically changing the motion at all and slightly rolling. I think its an axle shaft or in the rear end. You can definitely hear it in the rear so not transmission and driveshaft is tight.

The dealer has had my car for a week now and they could replicate the issue on a lift. They had to have a "specialist" diagnose what it is two days ago. They still have not 100% pinpointed the issue. They said they have been in contact with Ford, and they have no idea and there have been no bulletins. They are now trying to find a similar car to see if it is normal (the car hasn't done it since new).

Ill keep everyone up to date.

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[rorrerjp]

Here is the video from Shapeshifter

2021 Mach 1 A10 Clunk - YouTube

 

[sakman84]

I definitely heard it in the provided video from the other user. You are doing the right thing by getting the paper trail going on it and having the dealer inspect. I too suspect axle....

Will it clunk upon deceleration with no brake inputs, letting the car decelerate under its own power?

Id also try and test it in neutral, get to a speed a bit above clunk speed, shift the trans to N and let the car roll to a stop, see if it clunks when you slip to N or at the speed which it normally occurs.

If you are comfortable, I'd ask them to road test it to hear the issue, not just on the lift.

You can always ask if you can road test it with a technician in the passenger seat or vice versa and you can instruct him to drive in the manner which will trigger the issue.

That noise would not be "normal" in my book lol.....dealers....

 

[rorrerjp]

I have 12k miles on my car and it started right before winter so within 2k miles. In ShapeShifters video it looks like he only has 3k miles, so maybe not an axle shaft that soon?

I've only noticed it when very lightly braking. This car rolls so nicely I never tried rolling to a stop without brakes.

The noise you can even hear in parking lots. From a stop go into F and roll forward slightly, brake to a stop, shift into reverse, start rolling backwards and it clunks, stop and shift into forward, roll and it clunks.

I agree its definitely not a normal noise. It never did it new and anyone that hears it agrees its not normal.

 

[ChitownStang]

Does anyone know if the latest TSB for the A10 - 21-2357 applies to Mach 1's?

 

[ShapeShifter]

Glad you started this thread and glad y'all could hear the noise in my video. My dealer hasn't looked at mine yet because they told me they are so backed up I can't even make an appointment. They said to just drop the car off and they'll look at it with a few weeks..... So I need to get myself another car to drive in the meantime.

 

[Cobra Jet]

Does anyone know if the latest TSB for the A10 - 21-2357 applies to Mach 1's?

@ChitownStang
It applies to all S550's (and the other Ford models listed in the doc) with a 10R80 transmission.
https://www.mustang6g.com/forums/threads/2018-10r80-a10-most-recent-tsb’s-in-here.102918/page-4#post-3448620

 

[ChitownStang]

@ChitownStang
It applies to all S550's (and the other Ford models listed in the doc) with a 10R80 transmission.
https://www.mustang6g.com/forums/threads/2018-10r80-a10-most-recent-tsb’s-in-here.102918/page-4#post-3448620

Ok, cool. Do you know for sure?
I do know that the Mach 1 A10 is tuned a little different because if it’s better cooling and torque converter so that’s why I ask.

 

[Cobra Jet]

Ok, cool. Do you know for sure?
I do know that the Mach 1 A10 is tuned a little different because if it’s better cooling and torque converter so that’s why I ask.

The actual TSB in the link previously provided covers all 2018-2021 Mustangs with the 10R80. If the S550 is a 2022 M1 w/10R80, it should be covered by the same TSB - even if not currently listed in the doc. Usually Ford will send out revised TSB's to include newer model years (so far, a revised TSB isn't out for this subject matter yet).

 

[rorrerjp]

Well guys onto the second dealership. Dropped of my car Thursday and they replicated the noise on the lift but had to have a drivetrain specialist diagnose on Monday for warranty reasons supposedly. Call Wednesday and the service adviser told me they are still waiting to hear from Ford what might be wrong but its been left inside so dont worry. Mind you this is the car they said looks sharp on their floor and they wanted to buy it. The advisor told me he'd check with the service manager and call me Thursday (yesterday). As they were locating another gt with 10 speed to replicate the noise with.

I never heard anything so called today and told them I at least need a diagnose or I'm going elsewhere as it doesn't take a week to diagnose or "find a car to replicate the noise on". They got very defensive saying they are waiting on Ford, and nobody can figure it out and they don't want to get into the rear end if its the transmission and vis-versa. I told them you replicated it on the lift you stethoscope it and know were the clunk is coming from. They said they didn't want to get into the rear end if its the transmission and I said you simply rtv it and refill it. I asked if the TSB has even been done and he said he has no idea, I asked what do the notes say and he said it doesn't work that way the service manager needs to call me Monday. The guy started getting crappy with me saying noises are the hardest to diagnose; mind you I told them exactly how it happens, showed them when I dropped it off, and they replicated it on the lift. I said I'm picking it up today and the service adviser said that's good because the service manager actually prefers me to just pick it up.

Mind you I only called once to check in on it. I have an extra 10 miles on the odometer with both of my seats adjusted all haphazardly and lost about 8 mpg on my trip summary. I didnt want to leave it there in the first place but they either genuinely were waiting on Ford or they kept it on their floor to show it off since they have no other stock and joy rode it once or twice.

BTW If they did perform the TSB it did not fix the issue at all and its just as prevalent.

 

[Cobrajet70]

Possible MagneRide ride noise. Mine does it from time to time during the same situation, sounds like a control arm bushing or brake but can occur from any corner, I drove home a few times with Chassis ears and pinned it down to the struts. I've talked to our Field service engineer and was told its not uncommon to hear the Magneride doing its thing especially during lower speeds while coming to a stop or just moving.

 

[rorrerjp]

Second dealer had my car for 1.5 days. They couldn't replicate the issue. Maybe a temperature thing as it happened for sure 50-70*F and we've been in the 80's.

They performed TSB 21-2357 as the first dealer had no claim against my car yet so its possible they never performed the TSB. Ill keep everyone up to date if it fixes the issue.

*Edit 5/18 They performed TSB 22-2139 not 21-2357

 

[Andy13186]

Mine was clunking when going from reverse to drive and back, it was the axle thrust washers that broke.

 

[ChitownStang]

Second dealer had my car for 1.5 days. They couldn't replicate the issue. Maybe a temperature thing as it happened for sure 50-70*F and we've been in the 80's.

They performed TSB 21-2357 as the first dealer had no claim against my car yet so its possible they never performed the TSB. Ill keep everyone up to date if it fixes the issue.

I’m really curious to know if you feel any difference in the shifting with the new tune. I have no clunking or problems really, just can be harsh or erratic at times so I made an appointment for this Tuesday to have them do the tsb. Im now debating going because I don’t want any new problems from going to the dealership. I do all my own maintenance

 

[rorrerjp]

So far, the clunk noise has not been aggressive as it was in the past. I feel I can still hear it slightly however Ive been keeping an ear on it.

I cant tell any difference between my car originally and after doing the TSB. Maybe it shifts slightly slower and not aggressive however its nothing night and day noticeable. There has been a couple times upshifting in S+ mode between 5-6 that it hits hard and feels like a driveshaft just dropped but this has only happened maybe 3 times in 2k miles now.

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