2016 8 Speed Clunking When Coming to a Stop

[m3n00b]

5800mi 6.2L

 

 

It also does a single flair shift from 1-2 every morning when cold.

 

When coming to a stop where it shifts from 2nd to 1st around 3-5 mph it clunks and feels like I'm getting tapped from the back. I need to take it on a pretty long trip tomorrow with my wife and 4month old and I'm worried. Found this guy's thread where he says the torque converter is locking up for too long.

http://gmauthority.com/blog/topic/2016-sierra-8-spd-issue/

 

Did any of you guys experience this? Any insight would be appreciated.

[m3n00b]

Ok it seems to be fixed. Followed the C1 relearn outlined here:

 

http://gm.oemdtc.com/492/transmission-adaptive-functions-and-correcting-low-mileage-harsh-shifts-2015-cadillac-chevrolet-gmc

To Learn C1 (For 6-7 or 3-1 Shift)

 

Pressure & Volume Learns:

Note: It is recommended to utilize a road with a speed limit between of 30-45 mph (48-72 km/h) for this procedure.

 

Shift the transmission into 6th gear with the PRNDM in the M position. Obtain an engine speed between 1000 and 1600 rpm. Maintain this condition for a total of about 5 miles (8 km). Cruise control may be used and has been found to result in faster learning of the clutch values

 

 

Towards the end of the 5 miles I could feel the trans hunting around between 5-6 when cruising around 44mph.

 

 

It's smooth as silk when coming to a stop now. Friggn computers.

 

-tapa

[mookdoc6]

Nice to hear! It's a sweet set-up! 6.2L 8spd wish the Techs could properly dial these tranny's in. It seems that most eventually do require polishing up with shift points due to build tolerances etc. It's nice that we can compensate now for all this like excessive wear after 200,000 miles etc. But it makes it no fun in the beginning as we all assume it's broken etc.....wish the Techs new that Fast Learning is OK but driving it and dialing it in takes time!

[Uncus]

I was just going to add: I have a 2016 5.3 8 sp 2wd. From new it was fine then around 3K miles it started all the hard shifts, gear hunting, etc. that we read about so much. My plan was to just pay attention to the problem and wait till it got real bad so the condition would be more obvious when I took it to the dealer but before long all these issues worked themselves out and I'd say it's at 98% consistant operation now. It still has that irritating lag at a rolling stop but I consider that design as opposed to defect and I'm learning to live with it. It's definitely a different tranny than we have been accustomed to all these years but it's hard to argue with the mileage relative to the weight it's carrying.

[rickytickyshorth]

Ok it seems to be fixed. Followed the C1 relearn outlined here:

 

http://gm.oemdtc.com/492/transmission-adaptive-functions-and-correcting-low-mileage-harsh-shifts-2015-cadillac-chevrolet-gmc

To Learn C1 (For 6-7 or 3-1 Shift)

 

Pressure & Volume Learns:

Note: It is recommended to utilize a road with a speed limit between of 30-45 mph (48-72 km/h) for this procedure.

 

Shift the transmission into 6th gear with the PRNDM in the M position. Obtain an engine speed between 1000 and 1600 rpm. Maintain this condition for a total of about 5 miles (8 km). Cruise control may be used and has been found to result in faster learning of the clutch values

 

 

Towards the end of the 5 miles I could feel the trans hunting around between 5-6 when cruising around 44mph.

 

 

It's smooth as silk when coming to a stop now. Friggn computers.

 

-tapa

Is there a procedure for 15's with the 5.3 6 speed?

 

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