As the guys said above, "check the fill plug first", is good advice. Getting a Factory Service manual is even better advice. Now, to check the level, remove the fill plug and sick your finger into the case. If you touch oil. The level is fine. But you should change the oil if it's an unknown factor. After you check the fill plug. Remove the drain plug and catch the old oil. It will be disturbing to see the amount of metal pieces in this oil, but hopfully you will not find any large chunks. Clean the drain plug magnet. It mostly there to trap the metal than as a diagnostic! Let the case drip dry (about 30 minutes). Replace the drain and pump in new oil. I like RedLine Oils MTL <Manual Transmission Light) but there are others bost less and more costly. 3.5 quarts (?) (somebody correct this). If you cannot remove the fill plug, remove the reverse switch and use that as your fill port. I bought a 1 gallon mustard pump jar from the restruant supply (Smart and Final Stores in L.A.) for my dedicated tranny oil pump. Fill the case untill it starts dripping from the fill port and you're done.