Yeah, your hack guys killed it. Once a set of gears gets noisey, unless you catch it very fast, ithey will always be noisey. They might not brake... but they wont be quiet any more. If it was me... I'd just plan to replace them. the 489 uses either a soli spacer, or the factory crush sleeve to preload the pinion bearings. That is what you need the rotating torque wrench and 260 pound feet of torque to set properly. You dont need locktite when things are set up right... Most nuts themselves have a swedge so they lock themselves. I would simply budget on re-doing the center section completely, use the sapcer not the sleeve, and re-gear it. I always run a gasket on the center section, and you can get tthe gaskets and seals for the axle bearing adjustment plates too. IMO, do it all, do it right, and forget about it.