I use the J-D "polyurea" #TY6341 multi-purpose stuff for the spindles on my J-D 54C deck, and everything else I have, too.
Got a good deal on a case of it a few years ago ($1.40/ea for 1# tubes) and it seems like good stuff. I smear a dab on the wife's glider swing pivots when I drag it out each spring, and it handles all the rain and stuff without squeaking for a couple months.
Interesting note about the lack of grease fittings some guys mentioned - my nephew's J-D L130 tractor has on of those "The Edge" decks on it. The original spindles have no zerks, but the replacements (2 so far - made in China
) he got from J-D, do. Mebbe if they had zerks from the factory, he wouldn't have had to replace the spindles?