Oliver 990 Clutch, Transmission, PTO. If you are not finding what you need for your Oliver 990 Contact us here.. Be sure to get the service manual to help with clutch and transmission repairs. Most clutch parts listed here are new, but we also have many remanufactured clutch pressure plates and discs. We can even have your core rebuilt in many cases. Complete clutch kits including the release bearing and pilot bearings are a great way to overhaul the system and the best price. A transmission torn apart with gears and seals and washers lying about can put a strain on you without the parts manual. Pleas call us for help with manuals or transmission repairs on your Oliver.