My service four wheel drive light came on n not shifting good

Try rebooting the new computer . you may not have let it setup properly when installed . Start by disconnecting the battery for a few hours while its unhooked turn your lights on to deplete any residual power that may keep the computer from doing a complete reboot . when you do restart the truck let it idle for 5 minutes without touching the gas at all. then take it for a drive . don't rev the motor and don't drive heavy footed . this is the break-in period for the computer so it knows normal drive perimeters . if this gives no joy . Who rebuilt the trans and who put it in . If it wasn't you I'd be talking to them . Hope this helps