Noise from DCT

[uhhh_maks]

So I'm getting a weird intermittent sucking sound from the frontish area of my DCT.

2012 DCT 135i. Bought the car used recently and the DCT pan was pretty wet so I knew it was due for a service ASAP. Only drained about 4L of fluid from the pan. Did both filters, new pan, and gasket. Took ~6.5L of fluid after oil balancing with ISTA. FCP kit came with 7 so I figured this was good.

Basically immediately it started making a weird intermittent sucking noise. It sounds like a pump ramping up and down every 4ish seconds.

Google led me to a thread about the sucking jet pump and I thought I had my smoking gun. Dropped the pan again and sure enough, the ball in pump had flipped 180 deg. New one in, oil balance again, and the noise persists.

Here is a video of the noise.

In person it sounds more like fluid sucking past a flapping seal or something rather than metal on metal like it kinda does in the video.

I've searched around but couldn't find anyone with an intermittent noise like this.

Some have suggested that 6.5L is not enough fluid for the trans, since the full capacity is around 10L. I have no idea how much was in after 85k miles, so I might try putting some more in slowly and monitoring, but that's all I got.

Thank you!

[ihbase]

Did you solve this issue? My guess would have been incorrect fluid level.

[uhhh_maks]

Originally Posted by ihbase

Did you solve this issue? My guess would have been incorrect fluid level.

I would buy that it was incorrect level if I hadn't drained and filled it 3 times now all with the same results.

Either way I have an update: I dropped the pan again last night to find that the o-ring at the top of the suction filter (https://www.fcpeuro.com/products/bmw...ag-28107850148) rolled out of its groove upon installation. Easily avoidable mistake as you can see all the way around the seal if you crawl around a bit. Luckily the bore it sits in has a hefty chamfer, so the seal was still in fine condition.

I also had actually been trying the URO cast aluminum pan: https://www.fcpeuro.com/products/bmw...ts-28108070791

It was weeping fluid at the back so I returned it and got a Getrag pan to replace it. I would advise against the cast pan, it had a lot of flash and sharp edges left over from manufacturing, and the seal is a different design that did not seem to want to seal. I also think the metallic pan may have amplified the noise, some searches led me to other threads linking metal pans and weird DCT noises.

After reinstalling and refilling with the OEM pan, the sound was still there but was much quieter while laying under the running car.

With the undertray installed and the car on the ground I could barely hear it, making me question whether I just didn't notice it before my initial service, and the combo of the slipped o-ring and aluminum pan amplified it.

Either way, at this point I have checked and rechecked everything I could so I'm going to try to move on with my life and will keep and ear out for any change.