"kalansing" can be a lot of things.

the most common is the brake pad wear indicator. the sound is a warning device to tell you that you need to replace your brake pads. but this should be going on all the time, not just over 40 kph

other things you can check are the suspension (pero usually squeaks and lagutok ang problema dito), loose parts in the undercarriage (for me yung kalansing ko was actually a loose catalytic converter shield), or barya in the door pocket