My DCT sump / leak journey

pbondar

Sergeant
May 30, 2020
415
236
0
This is my personal struggle with my DCT box…

All was well until I decided to change the fluid and at the same time use a trendy alloy pan to look cool and carry a bit more capacity..

After my local low tech garage had fitted it, there was some very light oil seepage from the pan..maybe a drop or two of fluid if that per night.

I tried two or three times to subsequently get a garage to see to the leak without anybody taking me up on it..I wonder why..

I then got a ‘BMW service centre’ to change the o ring and refill it..after much drama with torque settings and having to get a fresh o ring airlifted in from the states.

However I noticed when driving along the odd puff of a burnt oil smell occasionally..when I got home the next day I could see a good patch of fluid on the ground.

I thought with 7 litres of fluid no big deal..

A couple of weeks later when trying to fo a full power 3rd gear test run for a new ECU tune it firstly prematurely shifted into 4th..on another run I then got ‘the bong’ with car going into limp mode.

Switching off and repeating the attempted run resulted in same situation.

My Protool code reader said..

5A44 clutch 1 incorrect pressure
5A41 Pressure sensor, clutch 1, total failure.

I pooed myself

Slowly drive home, rechecked the box..no errors.

Booked an appointment with same said garage..they then cancelled my appointment saying they were busy and they’d get back to me the next morning.

I went through the ‘if you need to get it done sometimes you just have to do it yourself.’

It looked like after cleaning everything thoroughly around the gearbox that the leak (when stationary ..no engine running ) iwas just from my after market alloy oil pan seal..

Side seal seems dry..couldn’t see the top seals / wire seal but was hoping it was just the bottom seal

Here’s are some photos plus the amount dripped out in 15 hours onto my wooden platform I usedfor crawling under the car..

I’ve bought a pressure filler and decided to fit my back up Polish alloy pan to see if the leaks stop..

Fair amount of damage to under tray plastics so got some alloy and pop rivets to repair some of the cracks ..

I dropped the ‘seems leggit’ alloy pan…

The sealing o ring had popped out from its groove so it wasn’t possible to see if it was seated properly..

However the fitter had used some grease to try and retain it prior to fitting..

When I inspected the o ring it came apart indicating that maybe it had been pinched..

More worrying was damage to the mating face in the same area..was he poking the o ring back in ?

You can see compared to the new Polish version that the Polish version has a thicker more positively located o ring..

3 litres of fluid came out…I think it should be at least 5 litres ..

Frustratingly the Polish pan uses the OE pan drain plug which was thrown away when the US pan was fitted..

My £16 new plastic drain plug arrived so I could start the reassembly can begin..

After loading 4.5 litres up then I had to use Bimmergeeks Protool as my ISTA for reasons I’ve yet to work out wouldn’t talk to the DCT as well as a couple of other ECUs..

Followed the same procedure with a couple of commanded shifts into 1st and 2nd for good measure..another 2 litres went in…

So 3.5 litres came out and 6.5 litres of Fuchs finest went in..

The dribbling out of fluid on the two fills felt like I was swimming in a sea of fluid.

I’ll take the car out for a 100 mile run on Sunday and see what gives.
 

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martymil

Major General
Sep 6, 2017
3,331
1,906
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Down Under
Ride
S65 1m
I always have the old mentality if it isn't broke don't fix it for this very reason, seen it happen so many times to people.

The extra fluid is not necessary, just change it more often like every 30k miles or less and upgrade the dct oil cooler.

Most won't have their cars long enough and move on to newer and better platforms.

I'm about to change my dct fluid and new oem pan and filter at 35k miles as its close to 14 years old, not km but because of age.

Oil does not last forever unlike what BMW claims as a lifetime fill.
 

pbondar

Sergeant
May 30, 2020
415
236
0
I always have the old mentality if it isn't broke don't fix it for this very reason, seen it happen so many times to people.

The extra fluid is not necessary, just change it more often like every 30k miles or less and upgrade the dct oil cooler.

Most won't have their cars long enough and move on to newer and better platforms.

I'm about to change my dct fluid and new oem pan and filter at 35k miles as its close to 14 years old, not km but because of age.

Oil does not last forever unlike what BMW claims as a lifetime fill.
Sadly and belatedly I agree with you 100%..but I did feel like I was doing something good…😳🙈😂
 

DirtKurt

Corporal
Nov 5, 2016
179
196
0
NH
Thats a bummer, have the slg pan on mine. No issues and good fitment. Definitely more of a bling item than a must have though.
 

houtan

Lieutenant
Nov 2, 2017
592
273
0
Ride
135i N55 DCT; PS2
Thanks for sharing. Where is the new pan from? Also, where is the fluid transfer pump from?
 

pbondar

Sergeant
May 30, 2020
415
236
0
Thanks for sharing. Where is the new pan from? Also, where is the fluid transfer pump from?
It’s a Polish company…compared to the American design much chunkier …


The filler is really good..with 7 litres it was the right tool…

 
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pbondar

Sergeant
May 30, 2020
415
236
0
Well looks like I’ve misled myself (as well as 3 other Indy visits)..my DCT sump leak is not really the sump leaking….its coming down from the external filter housing…I won’t itemise how much time, how many pans, how many fits and how many litres of DCT fluid I’ve gone through…😳🤔🙈👀👎

I may have had a sump leak early on..but since this is now leaking with no oil in the sump then..

It’s the way it glows around the sump pan…

Very annoying

Not to mention the sheared bolt by using ‘normal’ stainless rather than A4-10
 

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Krampus

Specialist
Aug 8, 2020
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Finland
It seems to be common that the o-ring of the pressure filter cover just dies. In the pictures, my friend's M4 oil pan and pressure filter cover. The cover of the pressure filter came off really easily and the o-ring was flat. With the new cover and o-ring, I struggled to get it in place. The oil pan was completely covered in oil before the filters and oils were changed. In Z4 and M4, the same filter, o-ring and filter cover set 28107842840. Oil did not leak from anywhere but the pressure filter cover, even if you wouldn't believe it from the pictures.


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pbondar

Sergeant
May 30, 2020
415
236
0
It seems to be common that the o-ring of the pressure filter cover just dies. In the pictures, my friend's M4 oil pan and pressure filter cover. The cover of the pressure filter came off really easily and the o-ring was flat. With the new cover and o-ring, I struggled to get it in place. The oil pan was completely covered in oil before the filters and oils were changed. In Z4 and M4, the same filter, o-ring and filter cover set 28107842840. Oil did not leak from anywhere but the pressure filter cover, even if you wouldn't believe it from the pictures.


View attachment 89011
Yup…that looks like my issue..an Indy replaced the filters work 25k miles / 3 years ago..

I was cursing him but maybe it’s just one of those things..🙈
 

pbondar

Sergeant
May 30, 2020
415
236
0
Well fitted new filter , filter cap and circlip…filled with 4 litres of fluid to let it settle …

As can be seen even though the sump is empty the leak gave the impression it was coming from the sump.

If you compare the old cap and its o ring it’s very much flattened compared to the fresh o ring on the new cap..

Took a good tap with the plastic headed hammer to fully seat it to allow the circlip to be fitted..

I’ll let it sit for a day and see..
 

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Dumaurier7

Lieutenant
May 19, 2020
514
198
0
Guess you really spent some long hours under your car huh?? pillow looks really comfy!!........😁😁
Nice to see you're getting there!


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pbondar

Sergeant
May 30, 2020
415
236
0
Haha, I noticed the pillow too - looks luxurious😀
😂🤔🙈😳

You forget what’s in the camera’s field of view….

At my age lying underneath for long periods on my back under the car either hurts my neck or head…

I did use a bit of curled up foam insulation with duct tape..

This version is a more upmarket version finished in nice hide…

I did use my mechanic trolley but with the plywood base I use on top of my scissor jack when I get it on blocks.. it’s too unstable ..moves way to fast …😂
 
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pbondar

Sergeant
May 30, 2020
415
236
0
Looks like the new external filter / cap / o ring fixed the mysterious ‘sump’ leak…

I’ve probably spent over £1,000 on pans, oils, filters to fix this…as well as 3 visits to 2 Indy’s .. :headbang: :headbang: :headbang:

Every day is a learning day 👍
 

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SLOWESTN54

Captain
Feb 9, 2021
1,237
973
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23
B.C. Canada
Ride
2007 E92 335i
I’m going to go reckless and tomorrow change the engine oil and try to avoid yet more leaks…wish me luck 👌😂
I bought a new car to get away from leaks, still couldn't escape them. My dad let me know there's a oil stain on the garage floor from where about the diff sits, told him it was likely from the 335i. Until I went and checked and turns out the M340 is indeed leaking diff fluid 😭
 
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pbondar

Sergeant
May 30, 2020
415
236
0
Well did the two step fill..took nearly 7 litres in total…looks dry underneath..;pushed my luck by doing an engine oil change..massively underestimated how far the hot oil would go sideways …spent most of the afternoon mopping up …6 litres of Fuch’s best ester based oil..and a nice Mahle filter..

 

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