Got a N55 noise I need help with

[neepertech]

*UPDATE(9/4/18) :This is a DCT Noise and is currently unresolved. Read through the post for the details. I'll keep this space as current as I can for those following.

Turn up the speakers a bit. I've been having this Groan/hum/vibration that happens ever few seconds while running. It's the womp womp sound you can hear in the vid. It's an 2011 DCT with 90k on it, The water pump and t-stat was replace at 75k.

Any ideas? Thanks guys!

[Havocsteve]

My first guess is belt related. But you'd have to check that first. After the belts, my next guess would the flywheel and trans area.

[juld0zer]

Disconnect the large vacuum line to the brake booster and see if you can eliminate/change the noise.

[OneWhite35]

I've had the exact same issue for the past few weeks... unfortunately I haven't been able to diagnose it. My windshield fluid reservoir has been empty for a while... wonder if it's the windshield fluid pump?

For reference, 2012 N55 DCT at ~90k KM (~55k miles). Water pump and thermostat replaced recently. No codes either.

[neepertech]

So I'm thinking it has something to do with the brakes. If I touch the pedal during the hum cycle it interrupts it. I have not gotten around to pulling the vacuum like from the booster but I will report back when I do.

So possible a bad booster, hard vacuum line, or vacuum pump. any other ideas?

Thanks!

[neepertech]

UPDATE: I just got out from under the car. I dropped the transmission covering tray. The noise is coming from inside the tranny pan. That's not good. I noticed the pan was wet so it will need a gasket and fluid/filter change. Does anyone know how the sucking jet pump works? item 4 on the diagram.

https://www.realoem.com/bmw/enUS/sho...diagId=28_0005

How do you check the fluid level in the DCT tranny. I've looked for write-ups but am striking out. HALP!!

[Happy Jose]

Originally Posted by neepertech

UPDATE: I just got out from under the car. I dropped the transmission covering tray. The noise is coming from inside the tranny pan. That's not good. I noticed the pan was wet so it will need a gasket and fluid/filter change. Does anyone know how the sucking jet pump works? item 4 on the diagram.

https://www.realoem.com/bmw/enUS/sho...diagId=28_0005

How do you check the fluid level in the DCT tranny. I've looked for write-ups but am striking out. HALP!!

I'd guess your fluid level is low due to a leak.

You need to get to a dealer ASAP! BTW, the transmission oil is $30/liter. I was told it takes 10 qts! The initial fill is good for the life of the transmission, but in your case, you need to repair the leak and restore the fluid level. Hopefully it isn't too late!

[neepertech]

Originally Posted by Happy Jose

I'd guess your fluid level is low due to a leak.

You need to get to a dealer ASAP! BTW, the transmission oil is $30/liter. I was told it takes 10 qts! The initial fill is good for the life of the transmission, but in your case, you need to repair the leak and restore the fluid level. Hopefully it isn't too late!

This is my assumption too. The transmission does not act any different than the noise. Shifts clean and crisp and I've never had it throw in to limp mode. I have my fingers crossed! I might try and replace the pan/gasket myself and change the fluid. I need to find my k=dcan cable first and get ISTA installed on my computer. I'm going to call the dealer tomorrow and see what they have to say first.

[Gangplank]

I believe the check fluid level is he same as filling it - pour it in until it doesn't fit anymore.

[OneWhite35]

Which noise are you talking about? In my earlier post, I was referring to the noise that happens periodically every couple seconds that sounds like an old projector advancing a slide. Sound occurs in your video at 5-6 seconds, 9-10, 12-13, 21-22, and 25-26.

[neepertech]

Originally Posted by OneWhite35

Which noise are you talking about? In my earlier post, I was referring to the noise that happens periodically every couple seconds that sounds like an old projector advancing a slide. Sound occurs in your video at 5-6 seconds, 9-10, 12-13, 21-22, and 25-26.

That is exactly what I am talking about OneWhite35. Get your car to the shop ASAP if yours sounds the same.

To verify it is the same or different with yours put the car SAFELY up in the air ON JACK STANDS, ramps, or lift and drop the undertray that protects the tranny. It took about 10 mins off and on. There about 7, 8mm bolts and the plastic tray rotates out of the way and drops loose of the car. Notice the diagonal pin on the passenger side that forces you to rotate the entire tray counter clockwise a few degrees to free it of the car.

I had my front wheels on ramps with the parking brake set. I started the car, crawled underneath and it was unmistakably coming from the transmission. With the undertray removed it was a lot louder. I was also able to feel the transmission pan and felt the vibration there.

Funny enough when feeling the aluminum transmission case and the mecatronics unit I could not feel the vibration/sound. Only from the plastic tranny pan. From what I can tell it is coming from directly on the other side of the pan. Looking at the parts diagram here https://www.realoem.com/bmw/enUS/sho...diagId=28_0005

this seems to be the suction pump. I wish I knew how it worked. The sound is like a servo that is groaning but the pump does not appear to be electric from what I can figure out in my googling. However, this has me thinking that it is low on fluid and scavenging. This is not fucking good at all. My only reservation that other than the noise the car performs flawlessly and has never been in limp mode or shown clutch slippage. I hope your noise is not from the transmission but if you have the same sound you better get it looked at or look at it yourself.

My car is stock with exception to BMW PPK and the required charge pipe upgrade. The OE blew off and broke many miles ago.

I'm hoping it just needs a tranny gaskipan replaced and DCT fluid change and all is fixed. We'll see and I'll keep you posted. Please do the same if you beat me to it.

[neepertech]

Originally Posted by Gangplank

I believe the check fluid level is he same as filling it - pour it in until it doesn't fit anymore.

I thought the same at first but I'm getting conflicting info from all over the place regarding topping off or even changing it. I wish someone would chime in that has done it before with success!

Does anyone have inside info on this procedure in the below video? (minus buying the $1000 transmission pan! I'll run another plastic one if I don't have to replace the whole DCT unit...) I found my k+dcan cable and am waiting on mega to let me download ISTA+ so I can check the module for codes and see if I can run a test. I see no codes on the OBDII side of things.

Half of me wants to fix this myself because it's a transmission and I've never owned a car that I can't service a transmission on. The other half of me wants to just throw my wallet at the dealership and hide in a corner.

Thanks guys. You're always awesome!

[neepertech]

So tonight I finally got ISTA+ up and running on my diagnostic computer and got it connected to the car. The DKG module is throwing NO FAULTS and idle temps at 104F which is what I assume is the higher range of idle. I say this because the Getreg unit has a sticker on the transmission that says only to fill between 86F-104F. I'm taking this as a good sign that nothing is broken and I just need to replace the pan/gasket to fix the leak and go through the refill procedure.

I did not run the car up 2k rpm in gear and check the temps like the above video shows. I figure I should make sure there is enough fluid to handle that first.

Half of me wants to just top the transmission off and make sure that it resolves the problem before I swap the pan and gaskets. The other half of me want's to go ahead with the drain/filters/gasket and fix the leak. If you want to weigh in with you opinions I'm all ears. At the end of the day $30 for a Litre of Pentosin Dctf-1 is a lot of money to throw away if I end up pitching it when I drain to fix the leaks. $500 is a lot of money if I have to "fix it the hard way" and I've gone down the wrong rabbit hole.

I'm still thinking I'd like to hear from someone who has done a filter replacement on the DCT before I commit to it.

For what it's worth I called my local dealer, BMW of DesMoines. I talked to a gal at the service desk who said the going rate for a pan/gasket and filter treatment is between $1000 and $1200. She was basing this off of what she has seen before but I did not get the impression that she was familiar with the differences between a regular torque converter auto, manual, and DCT. She was swamped and I didn't want to keep her from work. I'm guessing she is close due to the fact that 1: she's seen a lot more BMW repaired than I have and 2: parts/fluid alone push the $500


Links to sticker and parts cost. I'm not sure how many L of fluid this tranny takes. I keep reading and seeing different things

View post on imgur.com

Any BMW techs around here to set me on the right path?

[neepertech]

I may be getting somewhere now that I'm learning a little about ISTA+

Here is the top off procedure per ISTA Data R4.10.15

View post on imgur.com

[Gangplank]

I founda a few DIYs in a thread by searching for DCT Service.

Originally Posted by houtan

Few of diys.

http://www.m3post.com/forums/showthread.php?t=746269

http://e89.zpost.com/forums/showthread.php?t=442369

http://www.m3post.com/forums/showthread.php?t=457178

[PDXE82]

Any new info on this noise? I've had it since I purchased the car with 26k miles now at 40k. I always thought it was a normal noise to go along with all the other quirky noises these cars make. No codes or shifting issues other than the occasional throttle lag which was much improved with an adaptation reset. I don't see any visible leaks but haven't had the cover off.

[neepertech]

Update. 2 days after I connected ISTA+ to it there has been no more of the noise. It fucking stopped. All previous symptoms have been absent for about a month. I dealt with it for 3+ months prior. I was worried that it was a fluid level and the tranny was scavenging for fluid. I dropped the underbody pan today and pulled the tranny fill plug. IT WAS FULL! I'm at a WTF and FML point now. Noise has stopped, tranny is full of DCT fluid. I put the car on 4 point stands, checked level then pulled the allen plug and a good bit of the "lifetime" fluid ran out! I need to send back 2L of Pentosin DCT fluid back to ECS. I have no fucking idea what is/was wrong with it. No more noises, it's never acted bad. Just was really noisy and I still don't like it. I'm going to have the dealer change all DCT fluids and filters as a precautionary when I can get it to the city. The good news is is that it does not seem to be a catastrophic causing failure. I still drive the shit out of it and it always hooks up with no slippage. It's an awesome transmission. I did diagnose what I though was tranny pan leakage to a bad motor oil change. The motor pan was caked with overspill. It's all cleaned up now and will report back in a month or 2 with another trans fluid check.

Through the ISTA+ software you can run the tranny through the gear actuators with the clutch pack disengaged manually which I did. Maybe this cleared something up???? Hell if I know.

I'd like to add that the tranny has 93k on it and the fluid that came out looked good but had a dark tint to it. It looked like synth motor oil after 1k miles. Too dark for my tastes but what I would expect with a wet clutch with half the miles. This tranny seems to have an awesome filtering system. I've never done the transmissions any favors and am willing to beat the piss out of it to find a breaking point. It looks to be holding up though. It never slips, and always grabs under max torque. It did not smell or taste for that matter burnt or of abuse. I am familiar with wet clutches in bikes and this looks very clean. Getreg made a good one and I'm quite impressed.

I hate to end a thread this way but I DON'T FUCKING KNOW guys!

[R0CKET]

bite the bullet and take it to a shop for diag. depending where you live they'll charge anywhere from 125-200 and theyll tell you exactly what the problem is, then its up to you whether you can perform the repairs or not

[Elderado82]

+1

This is what I am doing, on Friday. As I have the exact same sound coming from the passenger side of the transmission. I'll keep you all updated on what my Indy says.

[neepertech]

Originally Posted by Elderado82

+1

This is what I am doing, on Friday. As I have the exact same sound coming from the passenger side of the transmission. I'll keep you all updated on what my Indy says.

Please do Elderado. I appreciate it!

[Elderado82]

Ok, took the car in on Friday to get the DCT looked at to see if there is a reason behind the light squawking sound coming from the passenger side.

Well my mechanic said its without a doubt the DCT making the noise. They got it up on a lift checked for leaks, nothing. Checked the fluid and filter for signs of grit or wear n' tare, nothing. Made sure it's running the latest firmware and it is. Checked for any inconsistencies with shifting, any grinding reports, pump issues, or pressure issues and found, well nothing.

The mechanic also contacted some others in his network of BMW mechanics and they have no idea why the DCT is making this noise. So I'm at a loss here as to why or what is causing this. Like yourself neepertech the car pulls very well and shifts well just has this noise.

If we have any other late model 135i's out there with a DCT that's making this same noise, I wonder? Or, is this a very rare circumstance?

[Yeineken]

Same noise. Have had it since I can remember. I had a family member who rebuilds transmissions look at it and listen to it while running on a lift. Figured out it's the oil pump in the transmission making the noise and it's not hurting anything.

Hope that helps.

2011 N55 DCT