Oil Pressure Sender

I have a 1996 Toyota Avalon XL special edition V6 engine. It has a major oil leak. I have narrowed it down to the oil pressure sending unit or the seals. Fairly certian the leak is coming from the sending unit (at least I hope it is). My question is: Do I need a special tool to remove and re-install a new one? It is very difficult to get to the unit by hand with out taking some of the belts off. I would prefer to leave those intact if at all possible. As for work done on the car, I have new timing belts, new water pump, new valve cover gasket, the tranie has been flushed (bad idea) and the last major tune up was done at around 160,000 miles. Current milage is 174,000. Please help.