4L80e + NP-246 is a problem w/standalone controller
Aside from the TPS any rig w/NP 246 AutoTrac has 3 speed sensors that sense frt driveshaft speed, rear driveshaft speed and road speed then the ABS is intergrated into that making for a PITA project going to standalone tranny control.
Reason for the 3 speed sensors, the NP246 has a clutch pack 9 clutches and 10 plates, when in autotrac everything comes into play and when slippage/or different speeds are sensed controller adjusts clutches as needed.
Any other t-case does not have the complex setup as a rig equipped w/NP246 does.
Hopes this helps ya!
99 GMC SUB, 2500, 4x4, 6.5 TD (F) #H32 enhanced blk, Phaser timing set, B&D IC, 3" ATS exh, K&N w/prefilter, 4WD NVG 246, 4L80E kevlar Transgo off road/tow mods/B&M supercooler, 14 FF MagTec w/locker 3.42:1, 9.25" IFS frt/diff 3.42:1 w/ARB locker, AutoMeter Boost & pre-turbo pyro meter, 12,000 lb hydro winch, Warn classic bumper w/brushguard & diesel scoop, Max E-torq Stage 3, hi pop inj, oil bypass sys, on board air comp for front ARB locker & tire inflation, DynaView driving/auto-cornering lts, DZ nerfs, A/T 285/75/16 SilentArmor 3750 lb rated on 3750 lb rated Alcoa, 3 IP drivers 2 r spares.