sprinter 516 ratio

[BIGBOYRS]

HI can you help me, i have a 516 2011 sprinter auto, at 60mph its pulling 2750rpm, i am trying to lower the rpm at 60mph to the same as my 316 sprinter 2015 which is 2000rpm @ 60mph, the 516 is twin wheel axle with a 4;8 diff any advice please, i belive someone before me had van remapped as it pulls like a train, not sure if anything can be done to auto box,
many thanks Simon