Reply To: Express 2500 Grade Breaking

I have a 2016 Express Van and a 2014 CTS both have the 6-speed automatic which has (down) grade breaking. It is only active in auto shift mode with cruise control engaged. The display may be shown on the first down grade transmission down shift during a cruise engagement. However, the engine tachometer can be used to see the the grade shift points. My CTS will hold the selected speed within 3 mph. My express van’s greater mass (8600 lb GVW) results on more speed over-run (5-7 mph). I usually click down the cruise to allow for this. Grade braking is one of the most important and useful transmission improvements made in the newer transmissions. It keeps you from getting speeding tickets on freeway down grades and saves brake pad wear too. Note that the old 700R4 rear wheel drive automatic had no engine breaking in 4th gear as it had a one-way clutch (in overdrive) , thus could over-speed the selected speed by as much as 15 mph or more. This led to more brake pad wear (and speeding tickets) as most drivers never read the owners manual that calls to move to D3 or D2 to hold vehicle speed. That works well because D3, D2 and D1 engage a band so that you have engine breaking. Bottom line is that grade braking is active on all down grades steep or not – as long as you have ENGAGED the cruise control. With out down-grade engine breaking on very long steep down grades – over use of vehicle brakes can lead to enough heat to boil brake fluid and then complete loss of all vehicle braking so be happy that you have it – you car is now much safer.