DCT Fluid Change?

I am a manual trans guy and a friend with a DCT car was touting that his car has permanent transmission fluid. In the past automatic transmissions require fluid service and manuals were considered permanent. To my thinking anything with moving parts requires fluid changes at some point.

So the question is to DCT owners- What is your trans fluid change interval? 37000 miles?

Three Pedal Steve wrote

I am a manual trans guy and a friend with a DCT car was touting that his car has permanent transmission fluid. In the past automatic transmissions require fluid service and manuals were considered permanent. To my thinking anything with moving parts requires fluid changes at some point.

So the question is to DCT owners- What is your trans fluid change interval? 37000 miles?

Steve, I had mine changed before 20k miles due to a leak fix. Didn't do it myself but the Tech said the fluid was like new. Reading around it could come out like new still at 50-80k miles while some is Brown earlier. Guess it depends on how the car is driven/cluch slip. Bottom line, can never hurt to get it changes. Obviously the life time bit is BS.

Getting mine flushed as we speak ~ 50k miles. Doing it as preventative maintenance since the car is now 5 year old and I figured that was long enough on the original fluid.

Three Pedal Steve wrote

I am a manual trans guy and a friend with a DCT car was touting that his car has permanent transmission fluid. In the past automatic transmissions require fluid service and manuals were considered permanent. To my thinking anything with moving parts requires fluid changes at some point.

So the question is to DCT owners- What is your trans fluid change interval? 37000 miles?

Not sure of interval, I also have 6MT, but always see this on ECS...

https://www.ecstuning.com/BMW-E90-M3-S65_4.0L/Maintenance/Drivetrain/Transmission/Service_Kit/ES2677651/

Changed mine as prevent at 51K mi. Anyone who thinks that is a lifetime fluid is taking a risk, esp. around the 90K mark.

Based on the various DCT fluid analyses I've seen posted on here, the fluid is still in good shape at 50k. My own fluid was looking great at 50k, and I do put DriveLogic in 5 almost all the time. I probably could've gone to 75k but oh well.

dparm wrote

Based on the various DCT fluid analyses I've seen posted on here, the fluid is still in good shape at 50k. My own fluid was looking great at 50k, and I do put DriveLogic in 5 almost all the time. I probably could've gone to 75k but oh well.

And guess the harder shift setting the less slip resulting in less fluid "wear"?

Everything I've been reading shows ~70k is a good time. Someone here sent in some fluid to Blackstone to get an analysis and it showed quite a bit of particulates.

My car has 103k on it and is on the original fluid. I'm literally right in the middle of doing a flush including both filters. I plan on sending it to Blackstone as well just as one more data point for the community.

nholmes wrote

Everything I've been reading shows ~70k is a good time. Someone here sent in some fluid to Blackstone to get an analysis and it showed quite a bit of particulates.

My car has 103k on it and is on the original fluid. I'm literally right in the middle of doing a flush including both filters. I plan on sending it to Blackstone as well just as one more data point for the community.

subscribed for the info!

What is the typical total cost, including parts and labor?

Mine was changed twice!
First at 35k and second at 65k.
And no, I didn't do it for peace of mind. It was part of its service interval?!

Not sure if it's the same for everyone else? Or even if it makes any difference, but as long as my DCT is in top shape! I have no complaints.

I did my 2012 dct at 75k miles and it looked new. I redline that car from day 1 constantly with s5 and s6 shifts always. That car went to 100k without an issue until I sold. On my now 2013 with 20k miles I won't be touching it until 100k unless it develops a leak or something that requires it. It truly is as lifetime as it comes as 70k miles of hard shifting and hard rev shifts and it looking new sold me

nholmes wrote

Everything I've been reading shows ~70k is a good time. Someone here sent in some fluid to Blackstone to get an analysis and it showed quite a bit of particulates.

My car has 103k on it and is on the original fluid. I'm literally right in the middle of doing a flush including both filters. I plan on sending it to Blackstone as well just as one more data point for the community.

Awesome, subbing for this

So I got around to replacing my orange o-ring at the metatronic connector on top of the DCT this weekend. In addition to that, I also did the full service to the DCT. This includes the fluid, suction and transmission filters. Getting that o-ring swapped is probably one of the shittiest jobs I've personally had to do on a car, but then again for me this is just a hobby.

I gotta say, for a "lifetime" part, the filters and fluid were quite nasty at 103,000 miles. It's quite a messy job, be prepared to catch a lot of fluid.

I also just dropped my DCT fluid sample for Blackstone off with FedEx today, so it will be a week or so until I hear back.

I'll let the pictures do the talking here:

Just change them both every 30K. What it costs you in parts and labor you should be able to make up for in resale to a conscientious buyer who will pay a few $$ for the piece of mind that the last owner went above and beyond with the mntc.

Tracyis300 wrote

Mine was changed twice!
First at 35k and second at 65k.
And no, I didn't do it for peace of mind. It was part of its service interval?!

Not sure if it's the same for everyone else? Or even if it makes any difference, but as long as my DCT is in top shape! I have no complaints.

There is no service interval for the M-DCT fluid. Are you certain you aren't seeing the rear differential fluid change?

dparm wrote  

Tracyis300 wrote

Mine was changed twice!
First at 35k and second at 65k.
And no, I didn't do it for peace of mind. It was part of its service interval?!

Not sure if it's the same for everyone else? Or even if it makes any difference, but as long as my DCT is in top shape! I have no complaints.

There is no service interval for the M-DCT fluid. Are you certain you aren't seeing the rear differential fluid change?

Nope! It's the DCT. And the diff was changed as well too! Lol
I guess the service is deferent at each location or something :

All i can say is that my car runs great! So I don't have no complaints

Tracyis300 wrote

Nope! It's the DCT. And the diff was changed as well too! Lol
I guess the service is deferent at each location or something :

All i can say is that my car runs great! So I don't have no complaints

Per the BMW maintenance booklet/owner's manual, the M-DCT fluid is marked as lifetime and is never supposed to be changed. It has nothing to do with where you live or what dealer you utilize for maintenance.

If the dealer did that for you at no cost, awesome...but they technically were not supposed to.

It might be lifetime, but the filters I pulled out at 103k were pretty gnarly.



Time will tell for those other cars that will never see any service.

I think BMW meant lifetime of the gearbox, not lifetime of the car. If you don't change it, the gearbox lifetime may be very short. Lol

Redd wrote

I think BMW meant lifetime of the gearbox, not lifetime of the car. If you don't change it, the gearbox lifetime may be very short. Lol

nholmes wrote

So I got around to replacing my orange o-ring at the metatronic connector on top of the DCT this weekend.

Can you elaborate on why the orange o-ring needed a change, was it leaking? And how the heck did you reach the top of the DCT unit?

Leonardo629 wrote

Can you elaborate on why the orange o-ring needed a change, was it leaking? And how the heck did you reach the top of the DCT unit?

I did it as a safety precaution since this car is a dedicated track car.

Reaching the connector requires dropping the diff and then the trans support. It will hang down far enough for you to reach back there and fish it out with a pick tool