Auto Grade Braking

[Skeld]

What is it actually doing to help slow down the truck?  Just a different shift program that holds the gear or downshifts more to try to take advantage of engine braking?

[Waaazooo]

What is it actually doing to help slow down the truck?  Just a different shift program that holds the gear or downshifts more to try to take advantage of engine braking?

Yes. Downshifts and works great. Scared the crap out of me when my truck down shifted and the rpms went to 3k in the Dmax.


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[dmax_ty]

It won't hurt em at all. Let it rev. 

 

In our Duramax equipped trucks we see 4k+ on a downshift all the time.  

[Jeff Lang]

Going down Oklahoma mountians my 6.0 got to nearly 5k... that caused me to freakout a bit.

[Waaazooo]

Lol. We only have 5k on the dial. I don’t know what it’s rev-limitation is. I don’t see a red line.


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[dmax_ty]

Waaaay back when GM first came out with the Duramax it would rev to the moon on a downshift and owners were shitting down both legs. 

 

They got tired of telling people that it's only doing what is was designed for so that's why they got rid of the red line at 3250-3300 from 01-05 and bumped it up for 06-07, then, completely got rid of it in 07.5 with the NBS trucks. 

[Sean Ramnauth]

Scared the crap out of me thr first time it happened but definitely helps esp with a trailer on the back

[SierraHD17]

I like it a lot with my 6 liter.  I have done exactly what it does manually for years and now its finally automatic lol.

[ewbldavis]

My 6.0 hasn't had a chance to do it yet.

 

My 5.3L would downshift and scream at like 6-7K. Took getting used to, but it does work!

[redwngr]

L5P 

Maximum Powered Speed    3450 rpm
Maximum Braking Speed    4800 rpm

 

Computer manages both