SMG still missing the up-shift from 3rd to 4th intermittently..

[ShiftLess]

still chasing this problem... track only car, just replaced SMG pump, GPS, actuator with MLR's stuff. Everything was installed and trained/paired etc. system bled multiple times etc. professionally by a shop with whom I have 100% confidence. I put the trans in S6 mode... Diffsonline track prepped trans... Kassel CSL TCU tune Epic Motorsports ECU tune. Car makes clunky noises when off throttle downshift as well ie into the toe at WG

thinking a TCU reflash? DTC ID 63 on Foxwell scan tool.

[zivagolee]

I think I have this same thing too! Car is mostly relegated to track only as well. I also used to get a lot of clunk off first gear (felt like a hard pop of the clutch) and I thought it was due to solid diff/subframe bushings but my shop seemed to have made that better.

At Sonoma, I would mostly lose 3->4 on the turn 9 sweeper unless I really eased going into 4th. I noticed if I shift around 6500-7k and left off the throttle half way, i can shift to 4th pretty consistently w/o issues.

Every so often I would get 59 (3b) and did all the recommended changes, still get this same code.

[oceansize]

I would check that your transmission compression springs aren't broken, common issue and when broken can lead to missed shifts.

[zivagolee]

I would check that your transmission compression springs aren't broken, common issue and when broken can lead to missed shifts.

Also, dropped tranny and checked springs.. no issues but changed them out anyway.

[sapote]

still chasing this problem... track only car, just replaced SMG pump, GPS, actuator with MLR's stuff. Everything was installed and trained/paired etc. system bled multiple times etc. professionally by a shop with whom I have 100% confidence. I put the trans in S6 mode... Diffsonline track prepped trans... Kassel CSL TCU tune Epic Motorsports ECU tune. Car makes clunky noises when off throttle downshift as well ie into the toe at WG

thinking a TCU reflash? DTC ID 63 on Foxwell scan tool.

Did they check the slave cylinder with position encoder?

[eacmen]

There is no Fault Code for decimal 63. Fault code 0x63 is hydraulic Pressure Sensor related. Might want to contact MLR if you're getting that code.

https://burkhart-engineering.com/en/smg-wiki/

[ShiftLess]

To Sapote: do you mean the gear position sensor? yes we changed that but did not change clutch slave...

Again, this only happened once during a three day WG event and generally only when I'm hammering...

[ShiftLess]

To Eacmen: also put MLR's on dash pressure guage on it so can see pressure... seems fine but I should have a camera on it to see if pressure is low when this happens...though when it misses 4th, I usually pull 5th immediately and then down to 4th without any problem...this issue was more frequent before wholesale replacement of everything...and I replaced everything because it had stopped working and was throwing codes for gps/actuator etc. ie I started car for my session and only got 4th and R, cleared codes, ran next session fine, back to pits and no R etc...decided I didn't want to find out how it fails at speed.

[sapote]

To Sapote: do you mean the gear position sensor? yes we changed that but did not change clutch slave...

Again, this only happened once during a three day WG event and generally only when I'm hammering...

I was talking about the clutch slave cylinder with the integrated position encoder (to be read by the SMG tcm during clutch activation).
GPS is also a position encoder and it's part of the shift rod actuator which you said it's new.

[eacmen]

To Eacmen: also put MLR's on dash pressure guage on it so can see pressure... seems fine but I should have a camera on it to see if pressure is low when this happens...though when it misses 4th, I usually pull 5th immediately and then down to 4th without any problem...this issue was more frequent before wholesale replacement of everything...and I replaced everything because it had stopped working and was throwing codes for gps/actuator etc. ie I started car for my session and only got 4th and R, cleared codes, ran next session fine, back to pits and no R etc...decided I didn't want to find out how it fails at speed.

If you're using their sensor tall to MLR regarding your error code 63.

[ShiftLess]

spoke with MLR... sent them this video shows SMG doing the clunka clunka doing into 3rd at the toe of the boot and missing 4th going into 11

https://youtu.be/S7-a44PAOBk

MLR suggested the clutch slave seal may be leaking internally so clutch slave will be replaced next week... we're also going to run a 3" air duct from the front bumper to get some airflow to the pump... hopefully after this I get some uninterrupted laps

[Irhase46m3]

Hi There - I assume since you have a diffsonline rebuilt diff everything should be tight with almost no play, if so, the clunk you are experiencing is either coming from that bad slave cylinder or the clutch bite point was not adapted properly (slave cylinder here) - if a foxwell tool was done to do this calibration i would not trust it, you most only use inpa for this, nothing else. Just confirm the shop used that

[eacmen]

Yeah INPA is the only tool to work with SMG.

[ShiftLess]

I'll check with the shop re which tool was used for the adaptations... what if they have a GT1 or DIS clone? it wasn't the Foxwell, I just use that to read/clear codes.

THANK YOU! in the meantime I'll attempt to download INPA onto my Win 11 Home Edition PC...
(will that work? or should I dig out one of the retired laptops around here and attempt to resurrect it?)

[eacmen]

Google mikes easy bmw tools and use that to install. Its the only one i've been able to get working with SMG