Allison 4000 series
The heavier Allison, for severe service, heavy vocational and off-road work at high gross weights.
Torque rating
1550-1850
pound-feet at the input
Weight
900 lb
260 lb over the lightest, which is payload
Shifting
Actuated
software decides the gear
Maker
Allison
What it does to fuel
The same converter losses as the 3000, at more weight. Nobody specifies one to save fuel.
What this type is
A true automatic with a fluid coupling. Smooth, forgiving and heavy, which is why it lives in refuse, mixer and city work where there are hundreds of stops a day and nobody wants a clutch.
Known issues
Weight, and the same absolute dependence on fluid maintenance.
Verdict
For heavy vocational work where shift quality and durability beat economy, which is a real category and is not linehaul.
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