Have you tried the temporary solution of releasing the tilt-wheel clamp, then pulling the wheel all the way to you and pushing it all the way down a few times. This spreads out any grease in that area and silences it for a time. Since its a non-moving joint, most any grease you can get on it will be fine. I would use Super Lube.
The grease is specified in the TSB, if you want to see if you have an equivalent or want to get a non-dealer priced item. Just check the dealer parts web sites for the specification.
WOW, I just checked the Stealership, $20, and no specifications, I will check my factory service manual and see if it is described there. I think in the past I just used a general grease that was viscose enhanced with fibers to keep it waterproof and meet all the needs of spline lubrication.