Front suspension “thump” noise/feel?

[wyobronco]

Had the same thing along with the squeal in the left front tire area. Replaced front drive shaft, squeal gone!, did a good 130 plus mile road trip, and no delay from braking to taking off. Seems solid now and I hope it lasts!

Dealing with EXACTLY this. Dealer hasnt been able to figure it out, going on about 10k miles like this. Thump under certain stop and start, and squeal from driver side when starting. So happy I found this thread, gonna take it to the dealer and print this out.

Is the consensus a pinion seal or what for all? Seems to be all over the place with a solution.

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[Ford Motor Company]

Dealing with EXACTLY this. Dealer hasnt been able to figure it out, going on about 10k miles like this. Thump under certain stop and start, and squeal from driver side when starting. So happy I found this thread, gonna take it to the dealer and print this out.

Is the consensus a pinion seal or what for all? Seems to be all over the place with a solution.

Hi there, Clint. This suspension noise concern doesn’t sound like something we want you to experience with your Bronco. Should you need further assistance, please send us a DM with your VIN and the name and location of your Ford dealer and I'd be happy to look into how I can assist you on my end. To send a direct message, just click on our username and select "Send Direct Message".

 

[Dude1967]

Dealing with EXACTLY this. Dealer hasnt been able to figure it out, going on about 10k miles like this. Thump under certain stop and start, and squeal from driver side when starting. So happy I found this thread, gonna take it to the dealer and print this out.

Is the consensus a pinion seal or what for all? Seems to be all over the place with a solution.

Trust me, it will return..

 

[JadeMyWorld]

It has started on my Bronco, sometimes a thump noise, sometimes a jolt, all subtle but noticeable. It happens right before a full stop or when taking off. Driveshaft sounds like the solution if the dealership admits the issue.

 

[mallaki]

I am experiencing the same issue with my 2025 Bronco Raptor with roughly 3K on it... When I come to a complete stop and again when I release the brake -- the truck gives a noticeable bump, stump or jolt. It feels almost as if a bowling ball in the back seat rolls forward just as the vehicle finishes stopping or starts moving again.

Another way to describe it is that it almost feels like auto start‑stop is kicking in, even though it’s turned off. This seems to be a long‑running problem. Other than the temporary relief from lubricating the slip yoke, is there any permanent fix?

 

[Darren D]

I’ve been having the same problem since about 4 months after purchase in July of 23. Subtle and very intermittent, at first. Then more consistent. First two times I took it in, the dealer couldn’t replicate. Frustrating, to say the least. Took it in a third time and rode in the passenger seat. Got the mechanic to feel the thump. Ultimately replaced the rear drive shaft, as there was a TSB on it. Less than a month later, the thump has returned. It’s in again. I found something else that says the PCM may need reprogramming. Quite a few people have had the reprogramming done and solved the thumping issue. I let the dealer know. We will see…

 

[Darren D]

Update:
Of course they couldn’t duplicate the problem. I’m letting them try one more time and then I’ll ask that they just reprogram the PCM, even if I have to pay for it.

 

[Darren D]

Last update:
Waste of time. Didn’t have my rig for two days. Of course when I dropped it off, it wasn’t thumping. They couldn’t duplicate the thump. Makes sense, right? Also, I’m told there’s no update to PCM, so no joy there either. Get this- I leave the dealer. Get 2 stop lights. THUMP. I MEAN WTF! I turn around, get to the next stop light. No thump. Turned back around and went home. I’ve dealt with it for 2 years. I’m done.

 

[mallaki]

I am experiencing the same thumping issue with my 2025 Bronco Raptor. After two days at the dealership, it was confirmed that this “feature” is by design. I just received the following response from Ford Crossroads Apex:

 

[Deadpool392]

I am experiencing the same thumping issue with my 2025 Bronco Raptor. After two days at the dealership, it was confirmed that this “feature” is by design. I just received the following response from Ford Crossroads Apex:

Interesting that they claim it to happen on another Raptor, I have not noticed any thumping coming from my Bronco, guess I’ll have to listen more closely.

 

[Nc211]

This sounds just like the driveshafts of the 2000's Toyota 4-Runners (had an 05' V8). It would do exactly what is being described here, and even note one poster got a new one and it came back. The solution on the 4-Runner was to grease the drive shaft via the zerks and grease gun. Would have to do it a couple times a year, and it would immediately go away, then slowly start to come back, signaling the need for service. The driveshaft slides in/out as the rear axle moves up/down. The thumping would happen when that sliding would get bound up. The thump would happen once you took your foot off the gas, releasing the tension, and the driveshaft would immediately adjust to where it's supposed to be with some force (instead of a gentle glide that you wouldn't notice).

It is my understanding that Ford has some type of "blue sleeve" thingy that's meant to be lifetime that allows the driveshaft to move in/out without the binding. They went this route instead of the old tried & true zerk method. We all know what "lifetime" really means. I suspect this thumping is that sleeve not performing at 100%.

Does it happen if you come to slow and gentle stop? Does it happen if you pop it into neutral as you come to a stop? Does it happen in the rain or snow? If right before you come to a stop and let off the brake for a split second then back on the brake, does it happen? These are scenarios were either the driveshaft is slick (rain/snow) or you're able to prevent the tension from happening. If it doesn't happen under some of these scenarios, then my bet is 100% on the driveshaft sleeve.

Maybe spray it with some silicone lube and see if that makes a difference? I don't know where it is on the driveshaft, I presume towards the rear differential like the 4runner was?

 

[mallaki]

@Nc211
I purchased the truck in November in North Carolina and didn’t notice any issues at first. Around March, I started feeling something, and since then it has become more noticeable - especially when the outside temperature is above 65°F. When it reaches 80°F or higher, the issue is very obvious.

There is no noise, but you can feel a noticeable bump. It happens consistently when coming to a gentle stop (normal street driving with traffic or stop signs) and again when I release the brake -- the truck gives a noticeable bump, stump or jolt. It almost feels like the auto start-stop system engaging, even though that feature is turned off.

I also found information suggesting that many newer Ford driveshafts use a sticky blue coating instead of traditional grease. Lubricating the slip yoke reportedly provides a temporary fix. I spoke with a local off-road shop, and within seconds of describing the issue, the technician knew exactly what I meant. He confirmed it’s a known binding and sticking problem and explained that lubricating the sdriveshaft and slip joint can reduce or eliminate the symptom temporarily. However, he recommended contacting Ford while the truck is still under warranty (it only has 7,000 miles and i noticed the issue since about 3K miles) to have them inspect and potentially replace the driveshaft.

He also mentioned that a more permanent solution would be upgrading to an aftermarket driveshaft designed to fully resolve the issue.

Here is a video that describes this :

 

[mallaki]

From Copilot AI:

2025 Ford Bronco Raptor Slip Bump on two piece driveshaft. It happens consistently when coming to a gentle stop (normal street driving with traffic or stop signs) and again when I release the brake -- the truck gives a noticeable bump, stump or jolt. It almost feels like the auto start-stop system engaging, even though that feature is turned off.

Copilot said:

What you’re describing is almost textbook Ford “slip‑bump / slip‑yoke clunk” behavior—especially with a 2‑piece driveshaft.
Why your symptoms line up

• Happens at a gentle stop → driveline unloads
• Happens again when releasing the brake / taking off → driveline reloads
• Feels like a single bump/jolt (not a repeated vibration)
• Can feel like auto start/stop engaging even when it’s off

That exact stop→release pattern is widely reported on Broncos/Raptors and F‑150s and is commonly traced to the driveshaft slip joint.bronco6g+1
What’s actually happening (simple explanation)
Your Bronco Raptor has a two‑piece driveshaft with a slip joint (slip yoke) that allows length changes as the suspension moves.

• The slip joint is supposed to slide smoothly in and out
• If it gets dry or slightly binding, it sticks under load
• Then when torque changes (braking or taking off), it breaks free suddenly

That “stick → release” is the bump you feel
This is exactly how slip‑bump is described:

• It occurs when torque changes (braking or acceleration)youtube
• It often shows up coming to a stop and pulling away from a stopford-trucks

Why it feels like start‑stop
You’re not crazy—this part is interesting:

• The drivetrain “loads/unloads” at very low speed
• When it re-engages suddenly, it mimics:
  • Engine restart feel
  • Transmission engagement shock

That’s why a lot of people initially think it’s a transmission or start/stop issue.
🟡 How common is this on Ford trucks/Broncos?
Pretty common across:

• F‑150 (especially with 2‑piece shafts)
• Bronco / Bronco Raptor forums
• Older Raptors as well

Some owners even report:

• Dealer replacing driveshafts
• Temporary fixes with lubrication
  bronco6g+1

How to confirm it’s the slip yoke (quick test)
There’s a simple behavior-based test (no tools needed):
At a stop:

1. Put the truck in neutral
2. Let it settle
3. Put back in drive and take off

If the bump does NOT happen, that strongly points to the slip joint binding rather than transmission backlash.bronco6g
Typical fixes (what dealers/mechanics do)
1. Re-lubricate slip joint (most common first step)

• Clean + apply special PTFE grease
• Often reduces or eliminates the bump

Downside:

• Sometimes temporary (can come back over time)

2. Updated parts / driveshaft replacement

• If splines are worn or coating degraded
• Some owners report full driveshaft replacement solving itbronco6g

3. TSB / service procedure (varies by model year)
Ford has historically issued procedures for:

• Cleaning splines
• Applying specific grease
• Re-clamping the boot
  fordservicecontent

Is it harmful?
Based on what’s documented:

• Usually not immediately dangerous
• More of an annoyance / drivability issue
• But:
  • Can worsen if splines wear
  • Could eventually require parts replacement

Bottom line
What you’re feeling is very likely driveline slip‑yoke bind (“slip bump”), not:

• Auto start/stop
• Transmission failure

Your exact “stop → release → bump” pattern matches the known behavior closely.
What I’d recommend next

• Bring it to the dealer and describe it specifically as “driveshaft slip bump / slip yoke bind”
• Ask if there are:
  • Service bulletins
  • Known fixes for Bronco Raptor driveline clunk
• Request a test drive with a tech so they feel it

 

[Darren D]

I just copied all this in a note and going to show the dealer next week. Thank you!

 

[Darren D]

@Nc211
I purchased the truck in November in North Carolina and didn’t notice any issues at first. Around March, I started feeling something, and since then it has become more noticeable - especially when the outside temperature is above 65°F. When it reaches 80°F or higher, the issue is very obvious.

There is no noise, but you can feel a noticeable bump. It happens consistently when coming to a gentle stop (normal street driving with traffic or stop signs) and again when I release the brake -- the truck gives a noticeable bump, stump or jolt. It almost feels like the auto start-stop system engaging, even though that feature is turned off.

I also found information suggesting that many newer Ford driveshafts use a sticky blue coating instead of traditional grease. Lubricating the slip yoke reportedly provides a temporary fix. I spoke with a local off-road shop, and within seconds of describing the issue, the technician knew exactly what I meant. He confirmed it’s a known binding and sticking problem and explained that lubricating the sdriveshaft and slip joint can reduce or eliminate the symptom temporarily. However, he recommended contacting Ford while the truck is still under warranty (it only has 7,000 miles and i noticed the issue since about 3K miles) to have them inspect and potentially replace the driveshaft.

He also mentioned that a more permanent solution would be upgrading to an aftermarket driveshaft designed to fully resolve the issue.

Here is a video that describes this :

I found this exact video last night, lol.

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