Smoked the brakes yesterday-update on test
Hi Folks. We have a 38' diesel pusher with cummins 350 and Allison trany. Built in 2008 and has 25,000 miles. Yesterday we had a 11 mile, 3500 foot winding, descent averaging about 8%. We used the e...
Forum Discussion
JimM68 wrote:
Engaging the exhaust brake on a dp automatically selects second gear, speed and rpm permitting
Let me qualify that.
Yes, 2nd gear is a common "pre-select" for exhaust brake, as is 4th gear.
And, when exhaust brake is turned on and throttle closed, the Allison starts downshifting TOWARD the pre-select gear. So, at highway speeds, that may mean a single downshift to 5th gear. As soon as speed drops enough that it can downshift to the next lower gear without overspeeding the engine it does so. Continue until the pre-select gear is reached.
Do not hesitate to use the down arrows-- they are "idiot proof". Even if you down arrow to `1st gear at highway speed, it will do exactly as above, ONLY downshift as soon as it will not overspeed the engine in that next lower gear.
