[RCW]

Use a non-clay based grease. Shell Aeromax, any Hydrotex product, and Lubriplate Syn-1600 series greases are non-clay based. The Hydrotex greases are the best, as they inhibit rust.

Regular automotive grade greases are mixtures of Bentonite clay, water, and oil. Some have moly added to help with lubrication when it starts to dry, but any clay in the mix is what does the damage. The oil dries out, the clay attracts more water, and becomes a fine abrasive that will walk out the splines over time.

In years gone by I used nickel based antisieze, but it has become priced out of sight. Do not use the antiseize for nuts and bolts, as it contains microscopic glass balls and will grind out the splines.

I grease my splines every year to keep them from rusting and wallowing out.