hino j08c speed limit non obd2

[4ly-syk]

hi all,
i have a 2006 hino gh truck with a j08c turbo engine.
i need to adjust the speed limit on the vehicle.
there is no obd2 connection on the truck. there is speed convertor box that is ontop of the ecu.

i have replaced it from a smaller truck with out a speed limiter. this changes the speed the truck reads. eg dash displays 102 but actual speed is 112)

is there away to turn of the limiter or adjust.

thanks for your help:champions:

[4ly-syk]

any ideas?

im pretty stuck on this