Hard Shifts

[bigman32hockey]

I have an '18 Silverado with the 6.2L.  From day one I have hated this transmission.  First I had the dreader "shudder" which they actually did fix with the fluid flush and new transmission fluid.  However, the trucl still shifts hard from 1st to 2nd almost all the time.  It clunks when I let off the gas and get back on the gas.  It's been to the Dealer twice and all I get is "It's operating as designed.  No codes".  Can someone on this forum whose mechanically inclined explain to me why the truck shifts hard from 1st to 2nd?  Is there any particular reason it does it, and if there is, what can I do to fix it?  I honestly don't care about the warranty anymore.  This thing sucks to drive around.  I would have it tuned, but from what I understand, you can't.  Any help would be greatly appreciated.  

[m3n00b]

You need to do some relearns.  I had the same issues.  I don't have time to find it but I've posted the procedure a few times if you look through my recent posts. 

 

 

 

Found it:

 

 

 

 

This is how I fixed it.

 

https://gm.oemdtc.com/6777/16-na-019-information-on-transmission-adaptive-functions-and-correcting-low-mileage-harsh-shifts-slips-or-flares-2016-2017-buick-cadillac-chevrolet-gmc

 

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

1. Pressure 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 engine 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.

2. Volume Learns:
   • Complete 15 light throttle 6-7 upshifts at approximately 15% throttle to further learn C1.

I also did this:

 

To Learn C4 (For 1-2, 5-6, or 7-8 Shift)

1. Pressure Learns:

Note: It is recommended to utilize a road with a speed limit between of 40-45 mph (64-72 km/h) for this procedure.

• Shift the transmission into 7th gear with the PRNDM in the M position. Obtain an engine speed between 1000 and 1750 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.

Important: Application Specific Express & Savana Vans Pressure Learns:Perform 10 normal mode 7-6 coast down shifts (zero/light brake) to learn the C4 Return Spring.

2. Volume Learns:
   • Complete 15 light throttle 1-2 upshifts at approximately 15% throttle to further learn C4.

Edited August 31, 2019 by m3n00b

[bigman32hockey]

So if I go to a parking lot and shift from 1st to 2nd in Manual mode 15 times at 15% throttle, the hard shifts should go away?