I have a 2000 Tundra 4X4 that has 8 grease fittings on the propeller/drive shaft. With a little maneuvering, all of the fittings are easy to grease with a standard grease gun coupler except for one. The furthest aft u-joint is aftermarket replacement and just doesn't have enough space to to couple with the zerc fitting properly. I can get grease all over the place, except into the u-joint through the fitting. So far I've tried needle nose and most recently an expensive Lincoln 5855 coupler with no joy...same problem. The fitting is perfectly clean, and the little ball valve on the zerc fitting seems to work fine. An internet search turned up a guy that ground down a standard coupler until it fit, but I'd like to just find a coupler that would fit without the grinding and work properly. Any ideas/suggestions? Thanks.