Q: Engine rattle on ford transit? Louder when reving oil level ok

Your engine rattle may be due to a failing catalytic converter or potentially a loose exhaust bracket since the sound gets louder with acceleration. As you may know, your catalytic converter has a honey comb like structure inside of it that helps to convert the toxic exhaust gases into less harmful gases to be expelled into the environment. When this structure begins to break down into small pieces, this may cause a bit of rattling as you describe. I would recommend having an expert from YourMechanic come to your location to diagnose your rattling sound.