DCT gearbox sump leak - 2nd in 2 years

[Busterboo]

Just had Electronic Damper Control unit replaced. Described in separate post. At same time, Sytner BMW did 'Vehicle Health Check' and identified 'gearbox sump leaking', which added £337.99 to the £659.04 already on the extended warranty bill.

Now, the point of this post is to ask, 'Do DCT gearbox sump plates & gaskets last only 2 years?', because the the last set were replaced in January 2019.

Or, like water pumps, are they replaced regularly as contributions to the mechanics' holiday fund?: 'Got a bit of a leak there, sir.'

(The car's parked undercover on clean - well, clean-ish - concrete and leaks are easy to see, but there was no evidence of anything.)

 

[Smartbear]

Could the leaks be masked from view by the undertray? If the leak’s from the same area as the last one you’ve got to wonder how well the work was carried out! :?
Rob

 

[2k35is]

Isn't BMW work warranted for 2 years as normal- what's odds of it being 25 months since it was done
EDIT Oops missed it was Jan 2019 so less than 2 years so below not a maybe but its down to them to sort

Surely some contribution from Sytners seems to be on cards

 

[Anonymous]

How many miles did the car do in the two ish year period?

 

[Busterboo]

How many miles did the car do in the two ish year period?

About 10,000 miles a year.

 

[Anonymous]

How many miles did the car do in the two ish year period?

About 10,000 miles a year.

Not a glowing indictment for that box for whatever reason....doesn’t seem too difficult to make a gasket that works..is it a stressed structure?

 

[Busterboo]

As far as I know, it's a matter of poor design.

 

[R.E92]

Did they replace the sump first time around or just the gasket? Sometimes the sump warps so no matter how many gaskets you replace it'll still leak.

Also possible that it's leaking from elsewhere and they are misdiagnosing. The DCT can leak from the sump and from a mechatronics cover gasket in the side higher up the box. It's also common for oil to leak from the engine (valve cover or oil filter housing) and make its way to the gearbox and look just like a gearbox leak.

 

[Busterboo]

Engine oil consumption remains consistent at 1 litre/10k miles, which it has been for 50k miles and which seems reasonable for this engine, so a 'damp/wet' gearbox sump gasket seems a reasonable diagnosis.

That said, I'm grateful for the prompt, R.E92, and I'll take the car to my local independent BMW specialist and ask what he thinks/can find.

 

[Mister T]

As far as I know, it's a matter of poor design.

Yep, very common issue.

 

[mcbutler]

R.E92 makes a very valid point, get under the ramp yourself when they get it up in the air.
Saying that though the sump trays are a plastic material and unfortunately they do warp and leak, Had my first one at 26000 miles so you are ballpark mileage for replacement at 20K if mine is anything to go by.
You can buy aftermarket Billett alloy sumps that give a lot better cooling and hang about 1cm lower, you will need a hole cut in the undertray to allow ther cooling fins to protrude into the airflow.
A worthwhile investment if you plan on keeping the car.

Example here,
https://www.n54tuning.com/bms-billet-aluminum-bmw-dct-transmission-high-capacity-oil-pan.html
its in the US but you can get them in the UK and on Aliexpress etc, most tuning manufacture stuff is Chinese in origin so dont worry about buying from them