Ideally you need to know what weight you will be towing.
Some transits (when laden) cannot even tow anything. But can if lightly loaded or empty.
Best way to check is look at the weight plate. Usually you will get (examples)

3500
4500
1500
2100


Top is gross vehicle weight, second is gross train weight, third front axle, fourth rear axle. NON of those plated weights can be exceeded legally.

In that example the max tow could be 2000kg, in theory this could be higher if the van weighed less than 3500. But I personally wouldn't risk it.

Note, if no second figure is shown, then the vehicle is not type approved at all for towing. Unless it's mega old.