allison tranny
well brought our 97 American dream home last night love the way it handles and drives question is going down hill is there a way to lock the tranny in a certain gear to keep it from shifting down to l...
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I'm not sure that all Allisons have a Grade Brake as such. Our 2002 DP does not have anything marked as such.
In order for it to shift down on a downgrade we must have have the cruise control engaged. This works well for most gentle hills. We switch on the exhaust brake and if cruise is selected it does add more speed control to the transmission on the hills, but the exhaust brake itself will not engage until we touch the service brake pedal. This of course turns the cruise control off.
You need to use the service brake to get you down to a speed where the exhaust brake and transmission will hold you at steady speed. We have descended many very long 6% grades an not touched the service brake after the first few times.
Our exhaust brake sets the transmission to select 2ng gear (it is a 6 speed Allison) but of course second gear will not engage if we are going too fast for it, which is of course the case at highway speeds. Normally it selects 3rd or 4th. If the speed gets too high for engine RPM the transmission will shift up. Hence the need for using the service brake to find the right speed to descend the hill.
A little practice and it will soon become second nature.
We love our Allion and Exhaust break. So much easier to drive in mountainous country than the gasser we had before.
In order for it to shift down on a downgrade we must have have the cruise control engaged. This works well for most gentle hills. We switch on the exhaust brake and if cruise is selected it does add more speed control to the transmission on the hills, but the exhaust brake itself will not engage until we touch the service brake pedal. This of course turns the cruise control off.
You need to use the service brake to get you down to a speed where the exhaust brake and transmission will hold you at steady speed. We have descended many very long 6% grades an not touched the service brake after the first few times.
Our exhaust brake sets the transmission to select 2ng gear (it is a 6 speed Allison) but of course second gear will not engage if we are going too fast for it, which is of course the case at highway speeds. Normally it selects 3rd or 4th. If the speed gets too high for engine RPM the transmission will shift up. Hence the need for using the service brake to find the right speed to descend the hill.
A little practice and it will soon become second nature.
We love our Allion and Exhaust break. So much easier to drive in mountainous country than the gasser we had before.
