A drive axle assembly for a heavy industrial vehicle, said unit comprising: - a support structure comprising a central body; - a first axle shaft and a second axle shaft aligned along a transversal direction; - a differential assembly housed in said central body and comprising: at least a first driven shaft and at least a second driven shaft; a first side gear integral with said first driven shaft and a second side gear integral with said second driven shaft; a first planet gear and a second planet gear both being splined on a central pin integral with said hypoid wheel, each one of said planet gears (6',β'') meshing with each one of said side gears (13', 13"); a hypoid wheel, coaxial with said axle shafts (10', 10'') and a pinion meshing with said hypoid wheel, said pinion being operatively connectable to an engine of said industrial vehicle, said hypoid gear and said pinion defining a first reduction stage of said drive axle assembly, and further comprising: - a second reduction stage defined by a first reduction gear placed between said first driven shaft and said first axle shaft and a second reduction gear placed between said second driven shaft and said second axle shaft, said reduction gears (20, 20'') being suitable to take a first operating condition wherein the speed of the corresponding axle shaft (10', 10'') is lower than the speed of the corresponding driven shaft (9',9'') according to a predetermined reduction gear ratio and a second operating condition wherein the speed of the corresponding axle shaft (10',10'') is equal to the one of the corresponding driven shaft (9', 9''); - switching means of the operating condition of said reduction gears (20', 20'') in order to switch the operating condition of said reduction gears (20', 20'') from said first operating condition to said second operating condition and vice versa, and wherein said first reduction stage is always active, while said second stage can be activated according to the conditions of use of the vehicle characterized in that said hypoid wheel comprises a cylindrical portion coaxial with the axis of said drive axle assembly, said drive axle assembly comprising first bearing support means which support said hypoid wheel, said first means occupying a position comprised between said differential assembly and said first reduction gear, said position of said first means being evaluated along said transversal direction. - a support structure comprising a central body; - a first axle shaft and a second axle shaft aligned along a transversal direction; - a differential assembly housed in said central body and comprising: at least a first driven shaft and at least a second driven shaft; a first side gear integral with said first driven shaft and a second side gear integral with said second driven shaft; a first planet gear and a second planet gear both being splined on a central pin integral with said hypoid wheel, each one of said planet gears (6',β'') meshing with each one of said side gears (13', 13"); a hypoid wheel, coaxial with said axle shafts (10', 10'') and a pinion meshing with said hypoid wheel, said pinion being operatively connectable to an engine of said industrial vehicle, said hypoid gear and said pinion defining a first reduction stage of said drive axle assembly, at least a first driven shaft and at least a second driven shaft; a first side gear integral with said first driven shaft and a second side gear integral with said second driven shaft; a first planet gear and a second planet gear both being splined on a central pin integral with said hypoid wheel, each one of said planet gears (6',β'') meshing with each one of said side gears (13', 13"); a hypoid wheel, coaxial with said axle shafts (10', 10'') and a pinion meshing with said hypoid wheel, said pinion being operatively connectable to an engine of said industrial vehicle, said hypoid gear and said pinion defining a first reduction stage of said drive axle assembly, - a second reduction stage defined by a first reduction gear placed between said first driven shaft and said first axle shaft and a second reduction gear placed between said second driven shaft and said second axle shaft, said reduction gears (20, 20'') being suitable to take a first operating condition wherein the speed of the corresponding axle shaft (10', 10'') is lower than the speed of the corresponding driven shaft (9',9'') according to a predetermined reduction gear ratio and a second operating condition wherein the speed of the corresponding axle shaft (10',10'') is equal to the one of the corresponding driven shaft (9', 9''); - switching means of the operating condition of said reduction gears (20', 20'') in order to switch the operating condition of said reduction gears (20', 20'') from said first operating condition to said second operating condition and vice versa, and wherein said first reduction stage is always active, while said second stage can be activated according to the conditions of use of the vehicle