Don't Touch that DCT !

[HFG]

Good day all,

Am preparing my E92 for some blower action and thought replace all filters and fluids. After preparing a list for all what "sensibly" requires changing, i called a trusted technician regarding the DCT filters and oil change. He said if your car has exceeded the 120,000km without replacing the fluid, then don't. I bought the car second hand (at 128,000km) where the first owner did all PM in the dealership. So, you can conclude that the DCT oil has never been changed along with its filters.

My question, is his advise solid ?

In a sense, if the clutches are already somewhat worn and got used to the oil, then reflushing and adding new filters will cause those worn particles to disappear and leave footprints that eventually will cause irregularities to the system. Hmmmm

P.S. my DCT works fine at the moment (139,000km)

[redline9001]

Switch the oil and filters .... bmw standard answer is life time amd not required but that is bs .

[SYT_Shadow]

so, his advice comes from regular automatic transmissions. In one of those, if the fluid inside is ancient and you flush new fluid in, the new fluid's detergent may dislodge some crap and ruin the tranny.

The DCT is *NOT* like this. The DCT fluid at 100k miles is almost completely clean.

You should definitely flush it.

[Redd]

I'm surprised ppl are still passing around these old advice from decades ago.

[deansbimmer]

"Lifetime" to BMW can be considered its warranty period. It's not a serviced item during that time span. It's not meant to mean the full lifespan of the car as long as it's rolling down the road- 200k miles, 30 years later, etc.

The fluid in these DCT is generally clean and quite usable even at 100k miles. However, there is no harm in changing it and can be beneficial. Much of the benefit comes from new filters etc. Traditional wisdom from automatic transmissions would suggest you can get into trouble if you replace fluid in a trans that is experiencing failure symptoms, but these DCT are almost always receptive to fluid services.

[wfdeacon88]

Originally Posted by Redd

I'm surprised ppl are still passing around these old advice from decades ago.

It's amazing how many "experienced" BMW shops don't know their way around this car. I know nothing except what I've learned on here, and before I found my current Indy, I was hearing totally incorrect shit over and over.

[Scharbag]

Originally Posted by wfdeacon88

It's amazing how many "experienced" BMW shops don't know their way around this car. I know nothing except what I've learned on here, and before I found my current Indy, I was hearing totally incorrect shit over and over.

Yup - it is amazing what people will say. Like "don't use an torque wrench with an extension..." Why? Think that one through for a moment. But over and over and over that old myth gets thrown around.

Or run ATF through the engine to flush it...

Or rod bearings have a break-in period...

Or a new engine should be driven gently for 1,200 miles (how the hell do you seat the rings??)...

The list can go on and on and on and on...

I am having a day...

[brettcp]

I had a little bit of DCT fluid seeping from the bottom pan gasket (common from what I've read here).. so I replaced my DCT bottom pan, fluid, and filters at 100k.. the new fluid looked much cleaner than the old stuff that came out. Was an easy job as well. Worth the peace of mind in my opinion.

[EvaaWilli]

Originally Posted by deansbimmer

"Lifetime" to BMW can be considered its warranty period. It's not a serviced item during that time span. It's not meant to mean the full lifespan of the car as long as it's rolling down the road- 200k miles, 30 years later, etc.

The fluid in these DCT is generally clean and quite usable even at 100k miles. However, there is no harm in changing it and can be beneficial. Much of the benefit comes from new filters etc. Traditional wisdom from automatic transmissions would suggest you can get into trouble if you replace fluid in a trans that is experiencing failure symptoms, but these DCT are almost always receptive to fluid services.

Now, unfortunately, all cars are the maximum guarantee period. Unfortunately I did not get a very successful car, I have already changed 2 motors.

[Bartledoo]

LMao

[SVH]

Originally Posted by Scharbag

Yup - it is amazing what people will say. Like "don't use an torque wrench with an extension..." Why? Think that one through for a moment. But over and over and over that old myth gets thrown around.

Or run ATF through the engine to flush it...

Or rod bearings have a break-in period...

Or a new engine should be driven gently for 1,200 miles (how the hell do you seat the rings??)...

The list can go on and on and on and on...

I am having a day...

Well, it's not a myth regarding breaking in a new engine for 1,200 miles if the engine is made with Alusil aluminum block and pistons.

[Scharbag]

Originally Posted by SVH

Well, it's not a myth regarding breaking in a new engine for 1,200 miles if the engine is made with Alusil aluminum block and pistons.

How is that now?

[SVH]

Originally Posted by Scharbag

How is that now?

There seems to be two schools of thought on the proper break-in methods. On rebuilt engines that are stroked and/or sleeved it seems the recommended method is drive it like you stole it. On non-sleeved rebuilds (Alusil aluminum pistons and block) the soft approach is recommended.

[Scharbag]

Originally Posted by SVH

There seems to be two schools of thought on the proper break-in methods. On rebuilt engines that are stroked and/or sleeved it seems the recommended method is drive it like you stole it. On non-sleeved rebuilds (Alusil aluminum pistons and block) the soft approach is recommended.

I am pretty sure that those who race ausil blocks do not drive gently for 1200 miles before racing the engine.

It makes no sense that the cylinder type would drastically change how you seat the rings properly. Gentle is bad. All the race engines I have dealt with get about 10-20 minutes of light use to make sure nothing is absolutely fooked and then within an hour it is at WOT. Change the oil after dyno tuning is done and away you go.

The 1200 mile break in specified by BMW is nonsensical for the engine. Perhaps the diff needs to bed in clutches but the rings, if driven properly, should seat within 50 to 100 miles. If the car is not driven hard, you risk glazing the bores. That usually results is greater oil consumption and reduced performance.

Cheers,

[SYT_Shadow]

Originally Posted by Scharbag

I am pretty sure that those who race ausil blocks do not drive gently for 1200 miles before racing the engine.

It makes no sense that the cylinder type would drastically change how you seat the rings properly. Gentle is bad. All the race engines I have dealt with get about 10-20 minutes of light use to make sure nothing is absolutely fooked and then within an hour it is at WOT. Change the oil after dyno tuning is done and away you go.

The 1200 mile break in specified by BMW is nonsensical for the engine. Perhaps the diff needs to bed in clutches but the rings, if driven properly, should seat within 50 to 100 miles. If the car is not driven hard, you risk glazing the bores. That usually results is greater oil consumption and reduced performance.

Cheers,

Speaking with Steve Dinan recently he confirmed what you're saying. A bit of light use, an oil change, drive it like you stole it, another oil change, off you go

[HFG]

Originally Posted by deansbimmer

"Lifetime" to BMW can be considered its warranty period. It's not a serviced item during that time span. It's not meant to mean the full lifespan of the car as long as it's rolling down the road- 200k miles, 30 years later, etc.

The fluid in these DCT is generally clean and quite usable even at 100k miles. However, there is no harm in changing it and can be beneficial. Much of the benefit comes from new filters etc. Traditional wisdom from automatic transmissions would suggest you can get into trouble if you replace fluid in a trans that is experiencing failure symptoms, but these DCT are almost always receptive to fluid services.

But a wet clutch is a wet clutch regardless...

I am definitely against BMW lifetime boll ocks.

Saying that, i doubt my DCT oil is clean, the car have been tracked, raced..etc up to 128,000km and now at 139,000km i dont think its a good idea to poke around. If it shifts right then, changing the (139,000km) oil might cause more harm than good meaning accelerating the non-critical failure creeping under the surface.

[HFG]

Originally Posted by Bartledoo

LMao

Glad u r enjoying ur time..

[deansbimmer]

Originally Posted by HFG

But a wet clutch is a wet clutch regardless...

The DCT and its wet clutch is not like any other transmission supplied in a BMW before. It's not like an automatic transmission at all. Conventional beliefs and A/T service practices do not apply.