2013 Silverado - dropping gears when coasting downhill

[DonnieBrasco]

I just got my first truck. Been driving an '03 Yukon for the last 15+ years. Just got a 2013 Silverado LTZ, 5.3L V8.

This weekend we had it camping in the Appalachians. On the interstate, when going down the grade, I would coast a fair amount. And I started noticing that when I was coasting, without pressing the gas or the brake, it would drop gears, and the RPMs would shoot up. If I hit the gas, it would drop back to where it should be. The only thing that really kept it from doing this was if I put it in "Manual" and managed the gears myself.

Is this normal?? I've still got some warranty on it from who I bought it from, so if this is not normal, I'd like to get it looked at sooner rather than later. Thanks.

 

[intheburbs]

From your owners manual, page 9-37

Normal Mode Grade Braking

Vehicles with a gasoline engine and
6-Speed automatic transmission
have Normal Mode Grade Braking
that is enabled when the vehicle is
started, but is not enabled in Range
Selection Mode. It assists in
maintaining desired vehicle speeds
when driving on downhill grades by
using the engine and transmission
to slow the vehicle. The first time
the system engages for each
ignition key cycle, a DIC message
will be displayed. See Transmission
Messages on page 5‑44.

To disable or enable Normal Mode
Grade Braking within the current
ignition key cycle, press and hold
the Tow/Haul button for
three seconds. A DIC message
displays. See Transmission
Messages on page 5‑44.

For other forms of grade braking,
see Tow/Haul Mode on page 9‑38
and Cruise Control on page 9‑59.

 

[DonnieBrasco]

From your owners manual, page 9-37

Normal Mode Grade Braking

Vehicles with a gasoline engine and
6-Speed automatic transmission
have Normal Mode Grade Braking
that is enabled when the vehicle is
started, but is not enabled in Range
Selection Mode. It assists in
maintaining desired vehicle speeds
when driving on downhill grades by
using the engine and transmission
to slow the vehicle. The first time
the system engages for each
ignition key cycle, a DIC message
will be displayed. See Transmission
Messages on page 5‑44.

To disable or enable Normal Mode
Grade Braking within the current
ignition key cycle, press and hold
the Tow/Haul button for
three seconds. A DIC message
displays. See Transmission
Messages on page 5‑44.

For other forms of grade braking,
see Tow/Haul Mode on page 9‑38
and Cruise Control on page 9‑59.

Thank you!