The service 4wd is on and I can't shift from 2wd to 4wd high or low range can any body help me figure this out. have changed encoder motor on transfer case and can shift transfer case by hand.2004 3500k Dmax

What truck and drivetrain? The most common problem is the switch on the dash goes bad. You may have to take it to a shop and have them pull the codes in order to get it fixed.

Sometimes it's cheaper/easier/faster to take problems to a reputable shop rather than shotgun expensive parts.