Volvo Repair: 2002-S60-Transmission Fluid, volvo transmission, exact transmission

Question
My car will be needing the transmission service soon, they say at 100,000 miles but getting it done couple thousand miles earlier.  Anywho, on my vehicle, what is the EXACT transmission fluid to be used?  Someone mentioned Dextron (spelling?) III and then someone else said a synthetic fluid.  Also, is it true that it takes gallons of fluid to flush out the system?  Also they said this type of fluid is very expensive.  He quoted me to have the service done for $400.  Is this true or is he trying to make money off of me?

Answer
Tanya, that trans uses the special synthetic fluid.  Do not put Dextron in there.  The trans will fail.  Take it from me, it has happened before.  There is no Specified Volvo Transmission service. All these bozos try to rip people off for fluid flushes.  He is trying to make money.  Roger