Code 82 means that the pressure switch is bad or wires to it are shorted or open. This causes the ECM (Trans. Controller) to go into self check for 30 seconds and delay the tractor from moving. It registers the code and enables the tractor to move after.
That is, in short, what the book says.
What is troubling with your description is the noise. The pump may have a problem developing pressure within the alloted time at startup causing the ECM to throw the code because it doesn't sense the pressure required. This would be equivalent to the sender not working or being disconnected.
You need to have it checked by a dealer for proper pressure and operation. If there is a problem with the pump, it could cause damage beyond just itself.
