CLUNK

[FlyingJat]

I have had my 85D for 13 months. Early on I would hear a loud clunk. Then it went away most of winter. Weather is warming up and the past two days the noise has returned.

It is a single that occurs if i accelerate hard. It comes from the back of the car and feels as if the axle was lose and banging into something. Can be either forward or in reverse. Happens less than 30% of the time. Usually I am going under 10 mph and then I hit the accelerator. I was a single clunk and then all good. About 2-3 months into ownership, I took it to SC. Of course the noise did not occur in their hands, nor with driving them in the car. Any ideas?

 

[csshih]

Warming up.. so you have water instead of snow? I believe it's your parking brake sticking(from rust), and when it's unstuck, a big CLUNK sound ensues.

 

[FlyingJat]

No snow anywhere near here. Rain yes. No rust, as it happened even when the car was new. Brake should be off as I am already rolling - usu 5 MPH

 

[ICUDoc]

Something sliding/knocking around in your cabin, "trunk" or "frunk"???

 

[FlyingJat]

Nope - nothing in the car but my body and stethoscope - which did not clunk

 

[Spurkey]

Warming up.. so you have water instead of snow? I believe it's your parking brake sticking(from rust), and when it's unstuck, a big CLUNK sound ensues.

That noise happens only when getting rolling after being parked (the parking pad has lightly fused to the caliper), this won't happen once the car's already rolling.

Could the noise be the traction control kicking in? You say it only happens when you "accelerate hard", next time it happens make a note of what the driving surface is, if it's relatively slick or if you can keep making the noise happen on that same section of roadway. My P85 makes a bit of a noise if I make a hard launch and the tires can't cope.

 

[FlyingJat]

Dry - sunny on paved road. Happens a bi tmore easily if I am starting a turn - but the noise is coming from the back

 

[EVgeek]

Dry - sunny on paved road. Happens a bi tmore easily if I am starting a turn - but the noise is coming from the back

Maybe rear differential issue. Happens more when back wheels are at different speeds. Turning, high acceleration. An idea.

 

[FlyingJat]

Yeah - it often occurs during a turn. Now just need to get it to service as it seems like an uncommon problem

 

[DFiveK2]

I had the same problem when I hit a pothole and it flattened out a portion of my rear wheel. I'd have your wheels inspected.

 

[Todd Burch]

If you're not aware (if you are flooring it or nearly so), you often get a clunk when the tires lose traction, traction control kicks in, and then it turns back off and the tires grab the pavement again. It makes sense that it might go away in the colder months, because the car won't put out quite as much power when the battery is colder.

As the pack warms up in the Spring, it can put out more power, and if you're near the traction limit it can come back.

The sensation in the car is that of a thud, as I would describe it.

 

[FlyingJat]

Thanks Todd - That makes sense!

 

[trils0n]

Traction control can certainly make a clunk sound as the brakes activate and slow down a wheel. Another clunk sound can result from insufficient lubrication of the splines. Gear slop feeling is another way to describe it. The CV joints can also make a similar sound and that can also be addressed at service center. (I've had a few clunk problems on my 2013 P85)

 

[chipmunk]

I notice Todd has a P85....not a dual motor car. The P85 is much easier to lose traction with because it has similar performance, but only using the rear wheels. I've had an 85D for about 10 months in a temperate climate, and my car definitely doesn't make a noise like that. It's really not possible for my car to lose traction on dry pavement, but even on wet pavement when it does, I don't get a clunk. I would have them look into it.