Engine oil capacity chart

4.7 litres of 0-30 0w-40 or 5w-30 longlife oil

most small engines have a sump capacity of 4 litres (convert that if in USA) with about 1/2 litre for the oil filter

Four things can give you a knocking noise. 1. failed rod bearing 2.failed main bearing 3. Bad piston wristpin 4. broken flex plate (auto trans)
If It's a bearing, likely you are seeing lower than normal oil pressure. Any bearing repair requires the pan to be dropped but to do the job correctly requires engine removal, crank re-grinding or replacement and oiling system cleanout (expensive). Wristpin (piston/rod assembly) can be serviced without engine removal but pan and cylinder head need to be removed. Flex plate is pretty much a trans remove and replace, with new wheel.
Only a good experienced tech can differentiate between the noises so I suggest you seek aid in your diagnosis, though, if either bearing or piston is the problem I'd likely find another engine before considering the repair.

Engine type 2RZ-FE manual trans. API GL-5/75w-90/2.7 qts.
Engine type 2RZ-FE Auto. trans. Dexron III/2.5 qts.
Engine type 3RZ-FE manual trans. API GL-5/75w-90/2.6 qts
Engine type 3RZ-FE Auto. trans. T-IV/2.6 qts
Engine type 5RZ-FE manual trans. Hypoid API GL-5/75w-90/2.7 qts
Engine type 5RZ-FE Auto. Trans. T-IV/1.7 qts

should be on vehicle some where or call manufacturer

if you have a 1ZZ engine

4.2 quarts, 4.4 quarts with oil filter change

if you have the 2ZZ engine (XRS model) it is

4.4 quarts, 4.6 quarts with oil filter change

NOTE these are updated capacities that reflect changes identified in TSB: TSB-0134-08 issued July 15, 2008.
Your owners manual will reflect a lesser quantity that Toyota has since revised.

if you have your owners manual, that info should be in the capacities chart

Look in the owners manual it should give you a time line or at about 60k

ask the dealer what kind of fluid they use or let them do it.wont cost much and maunal trans should be fine for at least 100000 km