Has anyone had an issue with a "clunk" when coming out of park or while braking?

C

Casey Martin

Active Member
This issue is fairly hard to explain but I will try to describe it. If I am parked on an incline and the car is in park when I enter into reverse or drive it clunks/slams into gear. This is with my foot on the brake of course. The car doesn't move but there is a clunk/slam in the drivetrain. This also happens sometimes while braking. The issue is not the mechanical brakes. I am positive of that. This issue is in the drivetrain it feels like.

I work for a Honda dealer but not in service. My service department is going to look into it next week. I imagine they will find the issue but I figured I would ask here if anyone has had this problem. I am currently at 117k miles and my Honda Care warranty expires at 120k miles. Hopefully the problem isn't anything major but I have a bad feeling the issue is in the transmission/drivetrain. I have changed my transmission fluid many times so I know the issue wasn't caused by contaminated fluid.

I will update this thread as I have more information. If anyone has encountered this problem please let me know.
 
Casey Martin said:
If I am parked on an incline and the car is in park when I enter into reverse or drive it clunks/slams into gear.
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The Clarity has a mechanical parking pawl (just like conventional vehicles).

If you are on a hill and shift into PARK (before setting the emergency brake) the pawl will engage and stop the vehicle from moving. This leaves tension on the pawl, so when it is disengaged later (by shifting into D or R) the pawl will 'clunk' when it releases this tension.

If instead, (when you are on a hill) you intentionally set the emergency brake before shifting into PARK, the brakes will be holding the car, and there will be no tension on the pawl, There will be no clunk when later shifting into D or R.

My point here is that it is normal to have a clunk like you describe if you don't pay attention to the sequence of the emergency brake and shifting into park.

Obviously you must feel that this behavior is 'new' because you are just raising the issue. But suppose you have always done the correct sequence when parking (emergency brake, then shift to park)... Maybe your emergency brake is worn (or needs adjustment) and is is not securely holding the vehicle on its own. This would also result in having tension on the pawl which would clunk when released.

It will be interesting to hear what you learn, but based on your description, it is possible that this is pretty minor.
 
I appreciate your response. I am aware of what you described. Unfortunately that is not what my issue is. My issue is a lot more "violent" than that. Also this issue can happen when braking usually after changing direction. For example, if I was to back out of my drive way and then drive forward sometimes the first time I apply the brakes fairly hard the clunk will happen. After it does the clunk once it won't do it again until I change direction again. Other times it will happen again after some driving. It almost feels like a broken engine mount allowing the drive train to move. One of my mechanics put it on the lift quickly and he believes the issue is play in the drivetrain as well. It is hard to tell though. The service department is gonna look at it next week. I am concerned because we have not seen many Clarity's with issues in our shop. Especially not ones with 117k miles on them. I know tech line will be able to help our mechanics but I was hoping someone here has had this issue to help me point them in the right direction.

Regardless there is something wrong. We have a used 21 Clarity in stock and it does not have this issue. I will update this thread as I learn more.
 
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Casey Martin said:
Also this issue can happen when braking usually after changing direction. For example, if I was to back out of my drive way and then drive forward sometimes the first time I apply the brakes fairly hard the clunk will happen. After it does the clunk once it won't do it again until I change direction again. Other times it will happen again after some driving. It almost feels like a broken engine mount allowing the drive train to move.
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It could be a loose/broken/worn electric motor mount, or in a component of the electric drivetrain. When you apply the brakes at speed the electric motor is used to apply all or most of the braking force. As you described it, this is actually the second time the brakes are applied rather than the first, if we assume that the brakes were applied after backing out of the driveway, prior to shifting into drive.

Below 5mph the friction brakes are used exclusively. So the electric motor wasn’t involved in the transition from R to D. Moderate acceleration from 0mph in either direction could cause a loose motor to move in the same way that applying the brakes would do the same.
 
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Casey Martin said:
This issue is fairly hard to explain but I will try to describe it. If I am parked on an incline and the car is in park when I enter into reverse or drive it clunks/slams into gear. This is with my foot on the brake of course. The car doesn't move but there is a clunk/slam in the drivetrain. This also happens sometimes while braking. The issue is not the mechanical brakes. I am positive of that. This issue is in the drivetrain it feels like.

I work for a Honda dealer but not in service. My service department is going to look into it next week. I imagine they will find the issue but I figured I would ask here if anyone has had this problem. I am currently at 117k miles and my Honda Care warranty expires at 120k miles. Hopefully the problem isn't anything major but I have a bad feeling the issue is in the transmission/drivetrain. I have changed my transmission fluid many times so I know the issue wasn't caused by contaminated fluid.

I will update this thread as I have more information. If anyone has encountered this problem please let me know.
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Check the wheel bearings. Especially the left front.
 
The wheel bearings are dead quiet. I just installed new tires and I can't hear any wheel bearing noise at all. I will check them for play though.
 
It does feel like a broken engine mount but that doesn't appear to be the issue. I will know more next week. I have a bad feeling the issue is in the drivetrain. I will find out soon enough.
 
Yes they have but they don't know what the problem is. I was able to duplicate the noise but only by parking on an incline and allowing the weight of the vehicle to be on the parking pawl. I know the normal clunk that type of weight transfer makes. This is more excessive than normal and they all agree. My concern is this same "clunk" happens when braking sometimes. Again, I know the "clunk" is not a hydraulic brake issue. I can feel it and hear it coming from the drivetrain. Well when I say drivetrain I mean the front middle of the engine compartment area. Duplicating the "clunk" while braking I have not been able to do. It has happened many times for me. Even my wife heard and felt it while she was in the passenger seat a week or so ago. Unfortunately I have not been able to duplicate the issue while driving with a technician.
Regardless they are working with Techline but nothing new to report as of now. Hopefully I have some new information soon.
I feel the issue is related to what ever the "parking pawl" is in this drivetrain. The noise is identical when it happens while braking. Maybe the regenerative braking system is catching the parking pawl sometimes but not often? I don't know but that is what is feels and sounds like to me.
 
You seem to be convinced that it is not related to the friction brakes...

If you made it a point to drive around in Sport Mode (with maximum regeneration selected via the paddle) I wonder if you would sometimes experience the clunk. You would need to do this in Sport Mode so that the maximum regeneration setting would persist throughout your drive. Although not really 1-pedal driving, this reduces the need to use the brake pedal and if it happened this way it would further exonerate any role the friction brakes might have.

Engine mounts were mentioned earlier... Sometimes an engine mount can fail in a way that is not visually apparent. While doing the sport mode experiment with maximum regeneration, you could perhaps exercise the engine mounts by intentionally alternating between acceleration and deceleration every second or two to see if it causes the clunk.

Obviously it is much easier to diagnose something that can be repeated in some way. Being able to duplicate the parking pawl sound doesn't help much because that sound is 'normal' (albeit perhaps excessive), but there is a subjective element there.
 
Casey Martin said:
I feel the issue is related to what ever the "parking pawl" is in this drivetrain. The noise is identical when it happens while braking. Maybe the regenerative braking system is catching the parking pawl sometimes but not often?
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From what you’ve described, the parking pawl theory sounds like a wild goose chase. We’re it to somehow engage, partially or completely, while applying the brakes at speed, it would surely shear off and create quite a commotion. Have you tried pressing the “P” button while driving at 50mph? I haven’t, but I’d bet the display will inform the driver that that function is not an option at the moment.

In EV mode the drivetrain and the breaktrain are the same thing. That’s the culprit.
 
Update: The issue appears to have been a torn lower torquerod mount.

I have only driving it for about 80 miles but the problem seems to be fixed. It feels much "tighter" when coming out of park or changing from reverse to drive. I haven't heard the loud clunking sound while braking in the 80 miles I have driven so far. I would like to drive it for a few hundred more miles to confirm it is fixed. It does appear to be fixed though. It is obvious the lower torquerod rubber was torn. I can move it with my thumb and you can see where the rubber is torn. The part number is 50890-TRW-A01 in case anyone else has this same issue. It is not that expensive of a part but it was hard to diagnose because when it is installed in the car the rubber didn't appear to be torn. With the lower torquerod removed it is obvious it is bad.

I will update this thread again after I drive it a few hundred miles to confirm it is fixed. I am glad my service department was able to figure it out. This was not an easy issue to diagnose since the clunking while braking was rare and very hard to duplicate. They were able to duplicate the clunk by driving slowly in reverse. It would clunk almost every time when releasing the brake while rolling backwards at about 5 mph. It wasn't as violent as when it would happen to me when braking at speed but the clunking noise was the same. Once they were able to duplicate the clunking noise they were able to narrow it down to the lower torquerod. I really appreciate all the effort my service department spent fixing this issue.
 

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Casey Martin said:
The part number is 50890-TRW-A01
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It is interesting to note that the Honda Insight uses this same part.
The Clarity does not have much in common with other Honda's, but the engine is mostly the same as the Insight, and this is part of the engine mounting system.

Glad you [hopefully] solved the problem (and if not for the difficult diagnosis it was a 'simple' problem) !
Just for reference, it looks like the part itself sells for around $80.
 
Correct MrFixit. You had mentioned it possibly being an engine mount in a previous post. My original thought was that as well. They checked them early on but again with the mounts installed they all looked good. That is why I started thinking it was in the drivetrain or something that had to do with the regenerative braking system. I am glad that wasn't the issue. The fix (hopefully fixed) was an inexpensive simple repair. Hopefully this thread will help someone in the future.
 
Casey Martin said:
That is why I started thinking it was in the drivetrain or something that had to do with the regenerative braking system. I am glad that wasn't the issue.
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Is it possible that the lower torque rod prevents the drivetrain components from moving when torque is applied from regenerative braking as well as when torque is applied from acceleration?
 
I would assume so. It is basically an engine mount that minimizes the movement of the drivetrain regardless of the direction that the torque is being applied. At least I believe that is correct.
 
While the drivetrain wasn’t the issue, per se, it was torque from the drivetrain that caused the issue to present itself. As you’ve mentioned, it was difficult to diagnose until the technicians were able to establish repeatable conditions.

A close examination of those mounts is something any owner should request as we near the end of our Vehicle Service Contract. Thanks for following through on this.
 
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