DCT Skipping Gears on Downshift

[Chris_PDX]

So, weird thing that hasn't happened in my 4 years of E92 M3 ownership:'

Four times in the last few weeks, when coasting or braking while downshifting my DCT has skipped a gear. Most recent was today, on the highway coming up to a stop light. I was in 3rd (unsure of speed, probably 35-40mph) and manually downshifted and instead of 2nd it went straight to 1st. It rev-matched, but still went up to nearly 6500 RPM.

Last time I noticed it was a 4th -> 2nd and the time before that was another 4th -> 2nd.

I have the GTS DCT tune (for about 3 years). The ECU software was just updated as I deleted EDC a few weeks ago, and oddly enough this has only happened since then. I'm taking it into my shop next week for something unrelated so we're going to look at codes, but I haven't had much luck finding anything online if this is a known issue.

Anyone ever had this problem? Other info below:

2012 E92 M3
Competition Pack
GTS DCT Software
Convenience coding has been done for some items (mirror fold, windows, etc.)
EDC delete as car as MCS dampers
Everything else is stock as far as electrics/software/drivetrain goes

[StripclubDJ]

Step 1: check fluid level
Step 2: remove flash
Step 3: do clutch relearn
Step 4 : if all else fails your mechantronic unit might be failing


I've had this issue on the f10 m5/6 DCT
3rd downshifting into first
Then getting stuck in first

Hopefully this isn't the case with yours

[roastbeef]

Are you absolutely sure you didn't double tap the paddle?
I have accidentally double tapped on an upshift, but most of the time when I'm in manual mode, I don't double tap a downshift because the rpms are too high and it gets denied- so it might happen and I'm not realizing it.

DCT will skip gears on a double tap.

[amrazM]

Originally Posted by roastbeef

Are you absolutely sure you didn't double tap the paddle?
I have accidentally double tapped on an upshift, but most of the time when I'm in manual mode, I don't double tap a downshift because the rpms are too high and it gets denied- so it might happen and I'm not realizing it.

DCT will skip gears on a double tap.

Likely a double tap. Do your buttons on the left side of the wheel all work?

[Shaan]

Originally Posted by StripclubDJ

Step 1: check fluid level
Step 2: remove flash
Step 3: do clutch relearn
Step 4 : if all else fails your mechantronic unit might be failing


I've had this issue on the f10 m5/6 DCT
3rd downshifting into first
Then getting stuck in first

Hopefully this isn't the case with yours

correct me if im wrong, but is draining the fluid the only way to see if its low? havent seen any other ways thus far

[StripclubDJ]

Originally Posted by Shaan

correct me if im wrong, but is draining the fluid the only way to see if its low? havent seen any other ways thus far

No
Put the car on the lift or 4 stands

Start and run it till trans gets to about 60c, pull the side fill bolt ( pass side) and see if it starts pouring out
If not , fill it whilethe car is running until a steady stream comes out

Or overfill it and put the fill bolt back on really quick

[Chris_PDX]

Originally Posted by roastbeef

Are you absolutely sure you didn't double tap the paddle?
I have accidentally double tapped on an upshift, but most of the time when I'm in manual mode, I don't double tap a downshift because the rpms are too high and it gets denied- so it might happen and I'm not realizing it.

DCT will skip gears on a double tap.

I'm 99.999% sure it wasn't a double-tap. That was my thought as well the first 1-2 times it happened, so I've been extra careful on that.

[Chris_PDX]

Originally Posted by StripclubDJ

Step 1: check fluid level
Step 2: remove flash
Step 3: do clutch relearn
Step 4 : if all else fails your mechantronic unit might be failing


I've had this issue on the f10 m5/6 DCT
3rd downshifting into first
Then getting stuck in first

Hopefully this isn't the case with yours

It has new fluid as of about 20 months ago do to a leaking side gasket. We inspected that when it was up for the suspension work a few weeks ago and nothing was seeping or otherwise indicated a fluid problem.

But... will check again

[StripclubDJ]

Originally Posted by Chris_PDX

It has new fluid as of about 20 months ago do to a leaking side gasket. We inspected that when it was up for the suspension work a few weeks ago and nothing was seeping or otherwise indicated a fluid problem.

But... will check again

Just for shits and gigs, try only downshifting with the center shift selector
Not paddles and see if it ever does it
And drive it constantly with down shifting

And report back

[dparm]

Agree, try using the shift lever instead of the paddles. Could be an intermittent short or something.

[Shaan]

Originally Posted by StripclubDJ

No
Put the car on the lift or 4 stands

Start and run it till trans gets to about 60c, pull the side fill bolt ( pass side) and see if it starts pouring out
If not , fill it whilethe car is running until a steady stream comes out

Or overfill it and put the fill bolt back on really quick

thanks for the info, need to try this next week

[amrazM]

Originally Posted by StripclubDJ

No
Put the car on the lift or 4 stands

Start and run it till trans gets to about 60c, pull the side fill bolt ( pass side) and see if it starts pouring out
If not , fill it whilethe car is running until a steady stream comes out

Or overfill it and put the fill bolt back on really quick

60C? You’re shot

Permissible gearbox opening temp is LESS THAN OR EQUAL TO 32C and you may fill it up to 40C.

If you want to verify fluid level open fill plug when cold, gear oil should be at the level of the fill plug.

[StripclubDJ]

Originally Posted by amrazM

60C? You’re shot

Permissible gearbox opening temp is LESS THAN OR EQUAL TO 32C and you may fill it up to 40C.

If you want to verify fluid level open fill plug when cold, gear oil should be at the level of the fill plug.

I do this for a living bud.

I know the fill can be done at 40c , or whatever you feel like

I've rebuild over 15 of these transmissions, I don't think you would understand why I recommend that temp
But thanks for providing the google service advice

[amrazM]

Originally Posted by StripclubDJ

I do this for a living bud.

I know the fill can be done at 40c , or whatever you feel like

I've rebuild over 15 of these transmissions, I don't think you would understand why I recommend that temp
But thanks for providing the google service advice

I’m sure you do,

Good luck to the OP opening the gearbox at 60C.

[StripclubDJ]

Not saying your wrong , becuz your right.




Op, does your place of service have a autologic ?

[Chris_PDX]

Originally Posted by StripclubDJ

Not saying your wrong , becuz your right.

Op, does your place of service have a autologic ?

Yup. I use AR Auto Service here in Portland. They have an Autologic box. Trying to make time to get in this week.

I work from home so won't be driving it until I take it over anyway in the next few days.

[Chris_PDX]

So just an update. Got the car into the shop today.

It hasn't been doing it for the last week and a half, using either the paddles or the shifter. No codes were being captured by the transmission, visual inspection didn't show any leaks.

Aside from the random skipping on down shifts it's behaving fine. We're thinking it might be a switch issue in the steering wheel where the paddles attach. So if it continues to do it, I'll replace that and see if it solves the issue.

Since it's so intermittent it's hard to replicate.

[roastbeef]

A while back when I got my aftermarket paddles, the downshift paddle didn't have a good connection for some reason. A little electrical grease did the trick.