you can spin a DT faster but why? you shorten its life according to navistar, and it makes it maximum HP at 2300. no reason to spin it faster than 2600..
when you say password lock, what all is Locked? VIN,ESN, Trans Type, RPM limit, HP, and EFRC are generally protected parameters that you can only use with ServiceMaxx L3.
do you have the adapter(nexiq or equivalent)?