Get a diagnostic done on it. Land Rover T4 will talk to your car, as well as the auto gearbox. Some independent garages also have it. Theyll be able to tell you what the fault code is, or if they can see whats failing. Other software available but it couldnt pick out the faults codes on the auto when mine was checked.
Dont leave it to chance. Mine needed changing and couldnt be saved.
If you tell us roughly where you are, someone may be able to point you to a known garage. Failing that your local main dealer will give a diagnostic for max £100. I know its not to some people taste, but all you need to know is the fault, at first.