DCT service PSA: the "Sucking Jet Pump"

[chocstraw]

Sorry to fill up this thread with a bit of my anecdotes, but on a whim I jacked up the right side my car, added 500-700mL of fluid, and 5 miles later, no issues.

Feeling like a bit of an idiot, because I've filled these transmissions going on 6-7 times now, no issues. Still a bit of [pump?] whine in reverse (usually a straight cut gear and not helical so it could be that), but otherwise it seems fine.

Not too mad, because the replacement transmission I got is flawless. Barely leaking, 2/2013 production date, so likely right at the end of the run. I was not able to get a mileage reading on it but judging from the interior of the car it was pulled from, very likely it's low mileage. It's barely leaking from the side gasket and sleeve seal.

Like Deans said, with a fresh check ball, it's much smoother coming from a stop at a cold start, no more clutch dumping or shock to the drivetrain. My checkball couldn't even form a proper seal from the wear.

[spammysammich]

Originally Posted by chocstraw

Sorry to fill up this thread with a bit of my anecdotes, but on a whim I jacked up the right side my car, added 500-700mL of fluid, and 5 miles later, no issues.

Feeling like a bit of an idiot, because I've filled these transmissions going on 6-7 times now, no issues. Still a bit of [pump?] whine in reverse (usually a straight cut gear and not helical so it could be that), but otherwise it seems fine.

Not too mad, because the replacement transmission I got is flawless. Barely leaking, 2/2013 production date, so likely right at the end of the run. I was not able to get a mileage reading on it but judging from the interior of the car it was pulled from, very likely it's low mileage. It's barely leaking from the side gasket and sleeve seal.

Like Deans said, with a fresh check ball, it's much smoother coming from a stop at a cold start, no more clutch dumping or shock to the drivetrain. My checkball couldn't even form a proper seal from the wear.

Please start your own thread for ease of search parsing later. Are you saying all you did was top off your old transmission?

[uhhh_maks]

I'm sorry to hijack this thread but I figure if anyone knows the answer to my question it's the people here: I'm getting a weird intermittent sucking sound from the frontish area of my DCT.

Bought the car used 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.

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 this thread 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.

Thank you!

[KawBoy]

Although I don't have the answer, I believe it is missing some fluid; mine took 9 liters at first and another one a few days later. I think 6.5 - 7.0 liters is not enough. Could it be that the pump is sucking air? I would try to add more fluid.

[uhhh_maks]

Definitely possible. I had 7 from the FCP euro kit, so that's what I used. I'll try jacking the fill side up and adding some more since that seems to work for some. Thank you!

[Brandoch]

Originally Posted by uhhh_maks

Definitely possible. I had 7 from the FCP euro kit, so that's what I used. I'll try jacking the fill side up and adding some more since that seems to work for some. Thank you!

Make sure that you follow the correct fill procedure. Including getting it to the specified temperature.

[Hivand_M]

A bit off topic but anyone try below DCT oil pan? Seems like a carbon copy of the OEM one but made in aluminum and is a bit cheaper, $156 vs $183 for OE.

https://www.fcpeuro.com/products/bmw...ts-28108070791

Ty for the PSA deansbimmer I'm at 40k and will also be changing the suction pump. Will post pics for science.

[Assimilator1]

That link isn't working for me, anyone else?

[uhhh_maks]

Originally Posted by Assimilator1

That link isn't working for me, anyone else?

Sorry, what link?

[KawBoy]

Originally Posted by Assimilator1

That link isn't working for me, anyone else?

Just tried it now and it worked.

[Assimilator1]

Originally Posted by uhhh_maks

Sorry, what link?

The link by Hivand_M

Works for me too now!

[Tibi_M2]

Dear All,
Just get this thread link from another topic, I'm searching for the reason of this sound what you can hear on the video, the car is an M2 N55 with DCT. Many of the M2's with dct having this sound, but also there is agroup where there is no sound, so it's confusing :/

The issue:
The sound comes ONLY in neutral, and loud only after cold start,
But its coming exactly 7 times in each minutes after 50 sec silence, 7 noise 50 sec silent and so on, if i change to gear 1 or R, the sounds stops immediatelly, and only comes again if i take it back to N, so its kind like expected/programmed. I have NO leaking on my dct, and there was no leaking before as well but ofc i don't know the oil level currently!

Question 1: Cold it be the jet pump?
Question 1: Is this unit electrical? Cause i check all the upper uploaded photos but i can't see any wiring/connection, but the name is still a pump, and pumps mostly electircal units i think!

Thanks for your help / comments

[Assimilator1]

I have no idea for DCT boxes specifically, but plenty of oil pumps are mechanical.
e.g engine oil pumps.

[Bimmer Barney]

deansbimmer any references for shops in CA that can do this service as you’ve described? Maybe MRF?

[Helmsman]

Originally Posted by Tibi_M2

Dear All,
Just get this thread link from another topic, I'm searching for the reason of this sound what you can hear on the video, the car is an M2 N55 with DCT. Many of the M2's with dct having this sound, but also there is agroup where there is no sound, so it's confusing :/

The issue:
The sound comes ONLY in neutral, and loud only after cold start,
But its coming exactly 7 times in each minutes after 50 sec silence, 7 noise 50 sec silent and so on, if i change to gear 1 or R, the sounds stops immediatelly, and only comes again if i take it back to N, so its kind like expected/programmed. I have NO leaking on my dct, and there was no leaking before as well but ofc i don't know the oil level currently!

Question 1: Cold it be the jet pump?
Question 1: Is this unit electrical? Cause i check all the upper uploaded photos but i can't see any wiring/connection, but the name is still a pump, and pumps mostly electircal units i think!

Thanks for your help / comments

The pictures available on the net clearly indicate that the pump is mechanical, surely that must be the case in this application?

[DrFerry]

Originally Posted by Helmsman

The pictures available on the net clearly indicate that the pump is mechanical, surely that must be the case in this application?

I'm not so sure. To me the "Sucking Jet Pump" maybe electrical because the pump body has no obvious mechanical drive. It seems to "plug" into the mechatronix module off to the side. See the male nipple on the end.... Haha.
.

[spammysammich]

It’s not. There were no connectors on mine. Purely mechanical as far as I could see.

[DrFerry]

Originally Posted by spammysammich

It’s not. There were no connectors on mine. Purely mechanical as far as I could see.

Okay. I sit corrected. But what 'drives' such a pump? A belt? A gear? A shaft? Nothing shown on the images. Thanks for keeping me straight.

[spammysammich]

Vacuum. It just plugs into a port on the bottom of the transmission secured by a torx screw.

[DrFerry]

Originally Posted by spammysammich

Vacuum. It just plugs into a port on the bottom of the transmission secured by a torx screw.

Interesting. I would never have guessed that. A vacuum 'pump'. No wonder the words "Sucking Jet Pump" are used to describe it. Thanks.

[Bimmer Barney]

So it’s a male nipple sucker.

[Assimilator1]