2018 RST 10L80 harsh shifting

[Trides]

@NickTransmissions currently experiencing harsh shifts into 7 at 30 mph and more pronounced at 60 mph when accelerating on on ramp. Tech has confirmed harsh shifts from 7 to 10 on road test. Reset and road testEd with no change to harshness.

Installed new valve body, flushed converter, lines and installed new filter with no improvement.

Any ideas, could be solenoids, clutches, gears, converter or TCU?

 

[NickTransmissions]

@NickTransmissions currently experiencing harsh shifts into 7 at 30 mph and more pronounced at 60 mph when accelerating on on ramp. Tech has confirmed harsh shifts from 7 to 10 on road test. Reset and road testEd with no change to harshness.

Installed new valve body, flushed converter, lines and installed new filter with no improvement.

Any ideas, could be solenoids, clutches, gears, converter or TCU?

Sorry, I'm not familar with the 10-speeds, never having worked on them but generally speaking that kind of a problem is either valve body, electronics (pressure switches, linear solenoids/force motors etc) or electrical (shorts in the circuitry).

Any DTCs?

Any attempts to reset the trans adapts?

When you say "Tech" are you referring to a technician or a computer scan you did with a scan tool and took it on a road test yourself? If a technician, what type of tech (dealership, independent shop) and why couldnt the technician tell you what's wrong?

 

[Trides]

Sorry, I'm not familar with the 10-speeds, never having worked on them but generally speaking that kind of a problem is either valve body, electronics (pressure switches, linear solenoids/force motors etc) or electrical (shorts in the circuitry).

Any DTCs?

Any attempts to reset the trans adapts?

When you say "Tech" are you referring to a technician or a computer scan you did with a scan tool and took it on a road test yourself? If a technician, what type of tech (dealership, independent shop) and why couldnt the technician tell you what's wrong?

@NickTransmissions

Yes they reset trans adapts after road test.

Still under warranty so it’s the dealership tech.

I will check tomorrow with the tech about codes as I have been only talking with service about the new valve body replacement, fluid and filter change they performed.

willis

 

[NickTransmissions]

@NickTransmissions

Yes they reset trans adapts after road test.

Still under warranty so it’s the dealership tech.

I will check tomorrow with the tech about codes as I have been only talking with service about the new valve body replacement, fluid and filter change they performed.

willis

If its under warranty, let them handle it...my guess is they just swap it for another one unless they can quickly figure it out though not sure why they didnt diagnose it correctly initially...

 

[Trides]

@NickTransmissions Initial diagnosis for harsh shifting confirmed by dealer tech on #7 and #9 gear changes. Scanned P2098 Post Catalyst Fuel Trim cleared. Perform transmission adapt learn and still had harsh shifts.

Remove transmission pan, changed filter and dirty trans fluid. Installed new valve body and perform Transmission Fast Learn with GDS. Test drive had harsh shifting amongst more gears.

Replaced valve body again and flushed transmission but it still shifts harshly.

Perform ECM and TCM update, adapts resets, quick learn and test drive, still shifts harshly. Contact GM TAC for support.

***Key Learnings***

After the Adapt reset, the transmission needs time to perform and relearn the Adapts Learning. Driving aggressively will instigate the harsh shifting issues that existed prior to valve body replacement. Driving normally for a month with out trying to cause shift issues has allowed the normal shifts points to be learned and the harsh shifts have been eliminated.

Filter and fluid changes or flushes prior to 50K miles are recommended.

 

[NickTransmissions]

@NickTransmissions Initial diagnosis for harsh shifting confirmed by dealer tech on #7 and #9 gear changes. Scanned P2098 Post Catalyst Fuel Trim cleared. Perform transmission adapt learn and still had harsh shifts.

Remove transmission pan, changed filter and dirty trans fluid. Installed new valve body and perform Transmission Fast Learn with GDS. Test drive had harsh shifting than amongst more gears.

Replaced valve body again and flushed transmission but it still shifts harshly.

Perform ECM and TCM update, adapts resets, quick learn and test drive, still shifts harshly. Contact GM TAC for support.

***Key Learnings***

After the Adapt reset, the transmission needs time to perform and relearn the Adapts Learning. Driving aggressively will instigate the harsh shifting issues that existed prior to valve body replacement. Driving normally for a month with out trying to cause shift issues has allowed the normal shifts points to be learned and the harsh shifts have been eliminated.

Filter and fluid changes or flushes prior to 50K miles are recommended.

Thank you for the follow-up, Trides - glad you were able to resolve the issues...The more modern 6,8 and 10 speeds are definitely more finicky and require much more rigorous attention to following applicable adapt/fast learn and related procedures...Freshly rebuilt 4L60E and 4L80Es are very simple bolt-in and go jobs by comparison but not nearly as sophisticated...