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wolfe10 wrote: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.
Exactly. And unless you own one of the few Allisons that has been reprogrammed to only go to fourth....
They are idiot proof. The trans won't downshift if over revving is the result.
Turn on the exhaust brake. Take your foot off the gas. If the coach goes faster than is comfortable, hit the brakes to the point that it downshifts again.
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