RIP DCT? Rebuild or Buy New

[McIntoshMotorSports]

Here's the story.

Picked up a 2016 M3 with 63K at a dealership "as is". Car was one owner and at 21K miles reported this noise but nothing ever came of it, not sure if the owner didn't want to pursue a warranty claim or if the dealership refused. Taking it to BMW next week but wondering if anyone has had similar sounds to this? Also makes the same noise twice in 5th sometimes.

[horsepower_and_hounds]

SCH

[bsmf8x]

Never heard of this not common as far as I know

[///Mvy]

Sorry to hear of your troubles. Never fun, especially on a new car. The DCT in these cars seem to be pretty bulletproof, even pushing serious power. If it were me, I'd probably find a used replacement to drop in based on the typical longevity of them.

https://www.ebay.com/itm/Automatic-T....m46890.l49292

[McIntoshMotorSports]

Originally Posted by horsepower_and_hounds

SCH

huh? lol

[McIntoshMotorSports]

Originally Posted by ///Mvy

Sorry to hear of your troubles. Never fun, especially on a new car. The DCT in these cars seem to be pretty bulletproof, even pushing serious power. If it were me, I'd probably find a used replacement to drop in based on the typical longevity of them.

https://www.ebay.com/itm/Automatic-T....m46890.l49292

34K miles not too bad. Might just buy new though because you never know if someone launched tf out of that one either until it's hooked up to a computer and welp there goes 3K. Although it looks like they may have some sort of warranty. Thanks for this!

[aliiin]

Originally Posted by McIntoshMotorSports

huh? lol

SCH = Spun Crank Hub

Yeah, you don't want this problem

[McIntoshMotorSports]

Originally Posted by aliiin

SCH = Spun Crank Hub

Yeah, you don't want this problem

Right should've assumed that will probably do a one piece CH eventually once I do tuning, honestly just loving the car at stock power at the moment!

[2011ninja]

Originally Posted by McIntoshMotorSports

Right should've assumed that will probably do a one piece CH eventually once I do tuning, honestly just loving the car at stock power at the moment!

Originally Posted by McIntoshMotorSports

Right should've assumed that will probably do a one piece CH eventually once I do tuning, honestly just loving the car at stock power at the moment!

Best mod is meticulous maintenance and new tires

[McIntoshMotorSports]

Originally Posted by 2011ninja

Best mod is meticulous maintenance and new tires

For some reason the fronts have brand new A/S 3+ on them and PS4's in the rear, I can feel the lack of front grip so will definitely be changing that very soon. Car has zero oil leaks at the current mileage and is very clean underneath. At least one rear subframe bushing needs replacing and will probably do single piece CHF once tuning begins

[maddmatth]

Originally Posted by McIntoshMotorSports

34K miles not too bad. Might just buy new though because you never know if someone launched tf out of that one either until it's hooked up to a computer and welp there goes 3K. Although it looks like they may have some sort of warranty. Thanks for this!

They're really built tough, I wouldn't even worry about it. Besides, for the price of a brand new one you can probably go through about 3 used ones

[McIntoshMotorSports]

Originally Posted by maddmatth

They're really built tough, I wouldn't even worry about it. Besides, for the price of a brand new one you can probably go through about 3 used ones

Unfortunately you can only hook up a brand new DCT , can't register a donor car DCT to another vehicle. So rebuild or 9300 for brand new

[maddmatth]

Originally Posted by McIntoshMotorSports

Unfortunately you can only hook up a brand new DCT , can't register a donor car DCT to another vehicle. So rebuild or 9300 for brand new

No way? Can't you swap the TCU across?

[mfurse]

Hard to tell from this clip.

I had a worn synchro that made a noise shifting 2-3 and was repeatable when going along at a constant speed (like 40 kph) and dropping it into neutral and back into D: https://youtube.com/shorts/Iir9D6BIPvk

It turned out to be a prematurely worn synchro in the box and BMW changed it after an investigation that went back with Germany.

Does your noise sound anything like mine from onside the cabin? I don't think BMW tend to open the boxes to investigate they just swap them out and send the old one back... no doubt it could be rebuilt by an Indy with the right skills though?

[McIntoshMotorSports]

Originally Posted by mfurse

Hard to tell from this clip.

I had a worn synchro that made a noise shifting 2-3 and was repeatable when going along at a constant speed (like 40 kph) and dropping it into neutral and back into D: https://youtube.com/shorts/Iir9D6BIPvk

It turned out to be a prematurely worn synchro in the box and BMW changed it after an investigation that went back with Germany.

Does your noise sound anything like mine from onside the cabin? I don't think BMW tend to open the boxes to investigate they just swap them out and send the old one back... no doubt it could be rebuilt by an Indy with the right skills though?

This is exactly what it sounds like but also in 5th. Very curious on why BMW would have not fixed it under warranty, especially if it's premature wear from not topping the trans with enough fluid from factory

[Hoppyumr]

Originally Posted by McIntoshMotorSports

Unfortunately you can only hook up a brand new DCT , can't register a donor car DCT to another vehicle. So rebuild or 9300 for brand new

Do you have credible sources for this statement?

I tried to do some research last night and didn't really find much. However, I did read things regarding the previous DCT and mechatronics unit having an ESG unit that could be programmed using a software program called WinKFP - several mention capabilities of doing so. I wasn't able to find anything regarding this software and its compatibility with the F8X series cars. I suppose it isn't a big deal if the donor DCT can have its esg unit, or mechatronics as a whole, replaced with the one from the original (owners) car that is already paired with the owner's VIN, but that assumes the ESG that communicates with the car is good to begin with - it also assumes we have an ESG that can be swapped independently from the mechatronics unit, or I guess just replace the whole mechatronics unit with ESG at the same time.

For me, perhaps more of an important question is what is the exact purpose of NOT allowing the DCT to be replaced with a used unit if they truly cannot be just reprogrammed and put through a proper learning cycle to assure proper clutch plate pressures, etc. I wonder if there is technically a legal issue here in doing what they've done. Consider the somewhat recent APPLE court case with the iPhone battery life restrictions placed in their software lowering phone performance, thus forcing an upgrade. I'm sure BMW knows the expense of these and since the depreciation of their cars will likely render an easier decision to just buy a new car than it would be to blow ~13k+ on a new DCT that might be 50% or more of the vehicle value, assuming older age car, maybe 10-15 years old; I know at this price point people are already antsy about these things going south and the average F8x value is probably 50k right now.

Point is, I think it is ridiculous to prevent replacement of a whole used unit; how is it technically any different than replacing with a brand new unit, as they both would need to go through the learning process, right? Don't get all hoity toity BMW bullshit on me, as it's a legitimate question. What's an engineering response to this...

[McIntoshMotorSports]

Originally Posted by Hoppyumr

Do you have credible sources for this statement?

I tried to do some research last night and didn't really find much. However, I did read things regarding the previous DCT and mechatronics unit having an ESG unit that could be programmed using a software program called WinKFP - several mention capabilities of doing so. I wasn't able to find anything regarding this software and its compatibility with the F8X series cars. I suppose it isn't a big deal if the donor DCT can have its esg unit, or mechatronics as a whole, replaced with the one from the original (owners) car that is already paired with the owner's VIN, but that assumes the ESG that communicates with the car is good to begin with - it also assumes we have an ESG that can be swapped independently from the mechatronics unit, or I guess just replace the whole mechatronics unit with ESG at the same time.

For me, perhaps more of an important question is what is the exact purpose of NOT allowing the DCT to be replaced with a used unit if they truly cannot be just reprogrammed and put through a proper learning cycle to assure proper clutch plate pressures, etc. I wonder if there is technically a legal issue here in doing what they've done. Consider the somewhat recent APPLE court case with the iPhone battery life restrictions placed in their software lowering phone performance, thus forcing an upgrade. I'm sure BMW knows the expense of these and since the depreciation of their cars will likely render an easier decision to just buy a new car than it would be to blow ~13k+ on a new DCT that might be 50% or more of the vehicle value, assuming older age car, maybe 10-15 years old; I know at this price point people are already antsy about these things going south and the average F8x value is probably 50k right now.

Point is, I think it is ridiculous to prevent replacement of a whole used unit; how is it technically any different than replacing with a brand new unit, as they both would need to go through the learning process, right? Don't get all hoity toity BMW bullshit on me, as it's a legitimate question. What's an engineering response to this...

I'm with ya plenty of other DCT's are rebuilt fairly often, don't see a reason why we can't do it other than legality. The person that told me this is BMW tech for years now, PDI'ed E9X & F8X M3's but now owns their own independent shop.

The car will be going to BMW on Monday so will find out what their recommendation will be. Thinking at this point will likely do a SSP clutch pack upgrade and changeout all the fluid as well as a new pan. But if it's synchros it genuinely might not be worth to service.

Would love for someone to chime in about the communication between all the modules as that's what I have the least grasp on.

[McIntoshMotorSports]

And there it is, quote from BMW for 14.3K; yikes.

[bsmf8x]

2-3 shift is usually what I'm hitting the most WOT and so are other people, maybe that's why OP and another forum member seem to have issues with that synchro

[McIntoshMotorSports]

Originally Posted by bsmf8x

2-3 shift is usually what I'm hitting the most WOT and so are other people, maybe that's why OP and another forum member seem to have issues with that synchro

That would definitely make sense. Unfortunate that this was not taken care of initially at 21K when it was first reported. Dealership I bought it from disclosed absolutely nothing about the trans and had no indication from the person that did the PPI that the trans was toast.

[IVM3]

Given the history of the earlier issue, maybe you can escalate it to bmw to see if they will split the cost with you.

[McIntoshMotorSports]

Originally Posted by IVM3

Given the history of the earlier issue, maybe you can escalate it to bmw to see if they will split the cost with you.

That's what I'm hoping to do. If BMW won't do anything I'm likely going to take legal action against the dealership, regardless that the car was sold as is.