Community Forums

Grimreaper · 06-15-2011, 05:58 PM

I have a 2010 GMC with the factory brake control in it and I would like to know if anyone else has this and what they think of it. My 5th wheel is close to 16000lbs loaded and I have the brake controller set to the maximum, I know it works because if you apply the trailer brakes manually you can feel it working. But slower driving in town it feels like the truck is doing all the braking. The last truck I had I installed a Tekonsha P3 brake controller and you could feel it working especially in stop and go traffic when pulling through cities, I know there is a lot more settings on the aftermarket controller but I'm just curious what others think of the GM factory controller.

Frank P. Martin · 06-15-2011, 08:08 PM

My previous truck was equipped with an old-technology, pendulum-type, Kelsey Hayes brake controller. With the GM factory brake controller on my 2009 GMC, it was like I died and went to heaven-- brake-wise that is. The truck and trailer brake in perfect harmony. Stops are smooth whether uphill, downhill or on the level.

I think the maximum setting on the controller is a 9. I have mine set somewhere around 7 - 7.5.

When in tow/haul mode with the Allison on your truck (I can't vouch for the older Allisons), the converter locks up when it downshifts; all the way down to and including second gear. I'm wondering if what feels to you as the truck doing all the braking is really the truck itself holding back. You might be able to answer this question by taking the transmission out of tow/haul mode when in stop & go traffic. I'm sure you're going to notice that more braking power will be required to slow your combination because the converter doesn't lockup in the lower gears. Just be careful when you do this because everything's going to continue rolling compared to when you're in tow/haul mode..

In first gear there is no holdback in either tow/haul or normal mode unless you pull the gear selector down into "M" (manual) and, if needed, manually shift the transmission into '1' or take the gear selector directly all the way down to "1".

With all the hills here in western PA, I use tow/haul mode even when empty because the truck holds back so much when going downhill that it requires a lot less braking.

Sorry if I seemed to drift from your original question with all this transmission talk, but what I have written is what I have experienced with this awsome Duramax/Allison so far.

mhs4771 · 06-16-2011, 07:17 AM

I have the built-in controller in my 2011 and love it. It knows exactly what the truck is doing and applies the trailer brakes as need. Now, I do have the exhaust brake also, so the Duramax does a lot of the braking saving wear and tear on both the Truck brakes and Trailer brakes.

Techie · 06-17-2011, 07:19 AM

I have it on my 2011 Sierra 2500HD and love it -- easy to setup, easy to check and easy to apply trailer brakes automatically.

We tow a trailer rated at 11,000 lb and braking has worked great -- just finished a round trip from Washington -> Oregon -> California ->So Nevada in all kinds of weather and have no complaints whatsoever.