If the Porsche Dealer rebuilt the trans and I doubted it.
Items needed for a TIP Service.
1) TRANSMISSION OIL PENTOSIN ATF 20 LITERS 999 917 547 00
2) TRANSMISSION OIL HYPOID 80-90 1 LITER 999 917 545 00
3) OIL SUMP GASKET 986 397 016 00
4) OIL FILTER 986 307 403 0
This is what you need for a TIP service. The transfer case has it's on oil, a 90 weight gear lube and usually take less than 1 liter. The transmission takes a lot of oil, but there is a procedure on how it is done. After the old oil is drain and the pan dropped, the oil filter is replaced inside the transmission, a visible inspection is made for any metal shavings or debris pointing to problem. After that the pan is replace with a new gasket and torqued to specs. The tech then fills the transmission until oil runs out the fill hole. The engine is then started and the transmission is allowed to warm up. The internal transmission temperature is monitored until it reaches a certain temperature, then more oil is put into it until it overflows. The tech will then run the transmission through several gears and do a final top off.
Now if you get a pre-owned TIP. You will need to do the service and replace front and rear seals and axles seals. It's much easier with the trans out to take care of this.