Not sure we're apples-apples here. I have no problems driving in 4L on flat or moderate terrain. I don't think a beach and the desert terrain I'm usually on have much in common except some sand.
The specific scenario I'm referring to is when climbing an obstacle, and the throttle build-up that occurs. At the slightest throttle change, the truck will either lunge forward or completely dump torque and roll back; there's no middle ground where it just "crawls".
Comparing to a manual transmission, it'd be like pressing the clutch in when giving it a little gas, or revving up with the clutch at moderate pressure, and then just dumping the clutch pedal, where the vehicle won't stall, but it'll bump forward. There's no sweet spot where you've got just enough clutch pressure to give it some gas and it'll both move forward and slip just enough. My '08 Wrangler w/ 6MT was perfect for this, where you could be almost completely off the clutch and in 4L and the truck would just move.
Here's the video from my latest trip that really put me at my tipping point. See specifically:
https://youtu.be/hzffJ3nu-T4?t=230 — lots of rollback trying to avoid lunging up that rock just trying to position the truck. Around 5:38, I'm having to rev up quickly a few times to get any response and avoid rollback.
https://youtu.be/hzffJ3nu-T4?t=1119 — especially at 18:52 where it just catches and goes. Spotter thinks I'm trying to kill everyone, but in reality, the revs sounded like they were holding. Both lockers were engaged and there was no slippage until the 1st lunge, when a boulder broke loose under my left-rear tire. During that obstacle (and clipped from the video, after I suggested needing a manual transmission) even the spotter said he could hear the truck flare/rev up excessively, not move, then just catch.
https://youtu.be/hzffJ3nu-T4?t=1633 — in particular 27:39 and again 27:42...you can hear me trying to rev up just to move and barely get a response, then it just goes. Bear in mind I'm on a near 45° decline...how much throttle should I really even need?! The guys think I was going to launch it, and the whole time I was trying to feather it.
For all I know, maybe I suck at driving this truck and should give it all up. I am absolutely not the type of wheeler who just guns it through obstacles; frankly, I hate those sort of people. But what irks me the most is looking like some reckless idiot with no regard for his truck, when I'm not even remotely out to damage or destroy my truck (though it is an accepted risk).
@Mr_Reverse, admittedly, my two-pedal does need work and it is something I practice on occasion...I'm just never comfortable doing it. I don't trust my right foot enough. I'd rather pull the e-brake and throttle up.
@adamzan, I'd totally take that response-and-lunge over this no-response-and-lunge any day. The throttle response in my truck is quite responsive, but not knowing when it's going to connect is frustrating.
Anyway, this thread can probably die at this point. There's probably nothing "fixable" on the truck, so I either suck it up or get rid of it.