From what I've read, it doesn't sound like the quad motor "virtual" locked diff feature on the Rivian trucks works as well as a proper locking diff - its close but still slips occasionally. If I recall correctly their cheaper dual motor models don't have the feature either.
I imagine eventually the quad motor "virtual" locking diff solutions will probably get reasonably good, if Tesla decide to do a quad motor CT later.
I dunno what Rivian does, but I saw that Rimac does 1 motor per wheel, and each motor madly modulates itself during launch control to stop its wheel from slipping... Perfect, maximum torque, all the time.
As a bonus, a computer is smart enough to spin the tires at slightly different rates when turning, instead of dragging them along like a locked diff.
The quad motor Rivian produces 908 lbs/ft of torque which means each motor produces 908/4 = 227 lbs/ft. It has a single speed gear ratio of 12.6:1 meaning each wheel can get a maximum of 227 * 12.6 = 2860.2 lbs/ft wheel torque.
The dual motor Rivian produces 829 lbs/ft of torque which means each motor produces 829/2 = 414.5 lbs/ft. It has has a single speed gear ratio of 13.7:1 (11:1 front) in the rear meaning each rear wheel can get a maximum of 414.5 * 13.7 = 5678.65 lbs/ft wheel torque (4559.5 front) with brake locking diff.
Contrast this with a Jeep Wrangler which can put out 20,000 to 30,000 lbs/ft of torque to any single wheel through its torque converter, transmission, transfer case and axle gearing which can be over 100:1 in gear ratio and single ICE.
There are videos of Rivian's stalling rock crawling that are no issue for an old Jeep with weak engine due to lack of torque to the wheels. EV's will need lockers and probably at least two speed transmission to compete here, or they will need way oversized quad motors to make enough low speed torque without the gearing and lockers.
Perhaps the CT should have used a G Wagon as a reference: https://youtube.com/shorts/4i_rxRJXaiU?si=AIOX_16-UbzyIAID
It's fine for the buyers who will be collectors, posers and social media tools - but still worth giggling about because Musk has consistently bragged that it'll be a better truck than any other truck while also being a 'better car'...and yet it does worse than a truck designed to not really see anything more off-road than a jobsite or country dirt road because Ford can
I'm guessing a P1 Touareg/Cayenne, or even a first-gen Audi Allroad wouldn't have a problem.
And here's a Range Rover going up it: https://www.youtube.com/shorts/_00ah8lG4yk
It seems like the CT doesn't have the equivalent of a locking diff, and had essentially no articulation. It'll be fine for the target demo (on-road usage).
Both the Lightning and the CT clearly suffer from their weight, and their optimization for on-road performance. (in the lightnings case, it even seems to be on stock tires).