A 2090 parts tractor I am tearing down does have a couple of the early updates. The first is a external mounted relief valve which was to protect the trans housing from damage in the event of a 3 pt hitch cancelling linkage failure. If I remember correctly CASE knew this could be a problem and issued these valves to dealers to install on tractors that were sold. Obviously all tractors did not receive them and honestly I don't know how well they worked. Maybe some guys out there have experiences with them. The tractor with the good housing that I have has one and the tractor with the broken housing does not. I guess if I owned one of these models I would make damn sure my tractor had one installed just in case. The second pic shows the hyd. pipes which were part of a pinion shaft lube line kit. These were installed as part of a large update package that was to be dealer installed on those models. With the lube line kit a different torque limiter disc and thrust washers in the differential were installed also. There also through the years I have seen tractors which missed those updates. The torque limiters failed anyway, we did replace a fair amount of ring and pinions while doing the update and not many since so I am thinking the lube line might have helped. CASE did change to using a higher quality steel in the later pinion shafts. The first ones were brittle and chipped teeth easier and had just a woodruff key securing the parklock gear which was prone to shearing. The later had a splined on gear, a much better set-up. Rod.