Not sure 'bout that.  

My DoKa slows when I lift my foot; if I gear down, it slows more. I'm sure this is an oversimplification, but it's good enough for me. 

Karl Wolz
Sent from my electronic umbilicus

On Sep 14, 2013, at 10:55 AM, Ben <syncro@GMAIL.COM> wrote:

> On Sep 14, 2013, at 8:37 AM, Don Hanson <dhanson928@GMAIL.COM> wrote:
> 
>> That is why we encounter very slow trucks on the downhills
>> as well as the climbs....They've shifted to a low enough to hold their
>> trucks from gaining speed...and thereby they can control the heat they
>> create with their brakes.....
> 
> 
> If this statement is about very large trucks such as diesel rigs, this would be less than an accurate statement. Excerpt taken for Wikipedia which is accurate enough for this discussion.
> 
> "Diesel engines do not have engine braking in the above sense. Unlike petrol (gasoline) engines, diesel engines vary fuel flow to control power rather than throttling air intake and maintaining a constant fuel ratio as petrol engines do. As they do not maintain a throttle vacuum, they are not subjected to the same engine braking effects."
> 
> So, NO. Those trucks are not downshifting to slow down. They are using alternative mechanisms such as jake brakes. Ever notice that the diesel in your Vanagon & other VW's have an auxiliary pump to create vacuum for your brake booster? Same deal. 
> 
> 
> 
> BenT