2nd gear rumble/ rear wheel bearings

2004 tundra 4.7 v8 rwd sr5 double cab lsd @265k Ive done a ton work on it over the last 8 months, doing upgrades and blowen off maintenance. T-belt, water- p, Front calipers, rack and pinion, power steering lines, power steering pump, cam/crank sensors, lbjs, jbl uca's, lca bushings, bilstien 5100's, ome springs, all fluids, filters, abs sensors, 2- tss's, clock spring, torch aal (pleasantly surprised with the lift and leaf support, didnt see that coming) , rims 265/70/r17 AT tires, fuel filter, ignition coils (denso), plugs (ksp) speakers, 5 channel amp, fog lights, head lights, interior lighting, added accessorie fuse Block, bed lights, lights under hood, front/ rear cameras w/dvr, I still got to do slip yoke leak, u- joints, center carrier bearing,. My abs tone rings seem to be pressed too close to wheels which I think is the abs problem, (cheap scan says sensor) I will pull axle and take to shop, . My questions are do all the seals, bearings,t-ring ect go on the axle or are there seals deep in housing? 2nd is I'm getting a rumble in 2nd gear, everything eles is good , I still have a couple things I need to tweak but has anyone else had this 2nd gear rumble? Also correcting speedo, do I need zero. Cal? I don't know what diff gear I'm running but if I'm pulling axles and d shaft , what gear rate do yall recommend 3.8? 4.1? Other? It's crazy but now that it's good for another 150k I'm thinking about selling it. Only because I don't really need a truck this big. That and getting into this project makes me want to build something from the ground up with little to no computer parts , v-12 power and unheard of mpg,, I know, I know but dreams can come true.