U joints won’t cause slop in the steering. You need two people to check it. Idle the truck with your foot on the brake and shake the wheel back and forth. Have someone put their hand on every tie rod joint to feel for popping. On big lifted trucks it’s common the track bar brackets will crack and break. If no major popping or issues can be found, gearbox is most likely to blame.
06 King Ranch
Fass 200, Custom fuel lines, 225/100s, Thumper stage 2 hpop, WPE stage 3 intake, Mishimoto radiator, Flex a lite fans, BPD water pump, MPD oil cooler relocate kit, Intercooler pipes, Compounds built by me, etc etc etc
05 Eddie Bauer
Resealed entire motor @ 170k miles, new lifters, 6.4 push rods, studs, rebuilt the turbo, IPR egr delete, new injectors, new heads, new ficm board, coolant filter, intercooler tubes, regulated return, bunch of other new parts. Factory exhaust, cat gutted(wife's rig). Livewire with gearhead tunes. Should go a while reliably for her!
03 LB7 duramax the "daily/tow pig"
Lbz cp3, s475/stock twin kit, built trans, steel driveshft, amsoil bypass, secondary oil cooler built by me, fass, traction bars, trans cooler upgrade, dual alts, straight center link + tie rod sleeves, efi live, transfer flow/tool box tank, 5er hitch, other small upgrades.. and most importantly, STOCK HEADBOLTS! Just rolled 200k miles, twins installed @ 165k, daily driven on a "550 tune" tows 18k on a "475" tune.