RPM at different speeds?

[NicholasJGrimsley]

Can anyone with a stock 2018 GMC Sierra 2500HD Duramax (or like) share with me what RPMs your truck rides at while doing 22-27 MPH and also 57-65 MPH?  I recently had a NorCal Trucks Stage 7 leveling kit with Cognito upper control arms, Fox 2.0 reservoir shocks and Sulastic Shackles put on my truck and I feel like after install it is not shifting down and cruising at the same points it was before.  Didn’t think a leveling kit would impact it as much as it seems to have before doing any tire changes (stock tire still on) and was curious if it’s in my head that the transmission shifting points has been impacted by it.  Love the ride quality of that package and the Sulastic Shackles made a huge difference in ride quality when not towing the trailer or boat.  Thanks for any info in advance.  

[redwngr]

Mine shifts at lower rpm when the engine and transmission warm - perhaps that is what you are seeing?

 

After warmup. and at gentle acceleration it has shifts at about 33, 42 and into 6 at 53.

 

Once shifted it will hold the gears to lower rpm then the shift point (if throttle application remains 'gentle')

I'm sure they are programmed to hold the gear lower than original shift point to avoid excessive 'hunting' for the correct gear.