i need help with serious crawler tuning (vanilla d-series, no mods)

so i am building a rock crawler based on the standard d-series heavy duty chassis, i have the 44x14.50 R17 crawler tires running on 0psi for the most grip, with the 3 links solid axles in the front and rear. weighted with the weightpad in game, the truck weighs 2265KG in total, 1368KG on the front axle and 828KG on the rear axle

The main goal is to make it climb extremely good uphill with rocks in the way. the current issue is that in the attached video, the front end will lift up after slowly trying to climb over a rock uphill and will result in the crawler backflipping over crashing down the hill. another issue is that when the tires loose grip at the steep uphills and the wheels spinning through, after the wheels catch grip again (for e.g on a rock) the truck will start to bounce heavily, and when that happens i immediatly need to stomp on the brakes to prevent another flip (also is there a way to get more grip??? the 44 inch crawler tires give best grip right?). i think the issues will explain itself in the video where i attempt to climb this hill of what looks like 45 to 50 degrees

i think it all has to do more with the suspension tuning but no matter what i do more i just cant figure it out on how to make it more stable to prevent that front axle from pogo sticking off the rocks constantly

here is video link:

here is crawler config: https://drive.google.com/file/d/1naDyUpjQDz1ozrHbEkykGfuMKQ8mpBKP/view?usp=drive_link
its best to test it at the johnson valley map well atleast i test it there

(sorry i cant upload the files directly my setup for 2FA will not work)

 

Personally I would look at decreasing the overall weight before worrying a ton about the suspension tuning. Even with the small V8s, you should be able to get enough torque to spin those big wheels; you don't need a big heavy turbo diesel for that, and you probably don't need the heavy duty D-series frame, either. Unless what you want is make that frame with that engine specifically climb that mountain, I would swap them out for something that weighs less.

Second, I think this is more of an issue with, to put it lightly, line choice and technique than with suspension tuning. There's only so much suspension can do to stop you from flipping over after smacking full-power into the vertical face of a big-ass boulder. Let the crawler crawl, and when the tires start slipping, let off the throttle until they've got grip again. What's sending you ass-over-teakettle is all the bouncing you're doing from going full-send 100% of the time. The tires unload from the bounce, lose grip, and spin up. Then when the weight of the truck comes back down they've suddenly got traction again and send you for a loop.

At least, I think that's what's going on. I'm not an expert; I just sound like one.

 

i dont really understand why decrease the weight more? i already decreased the weight by a lot and keeping as much weight as possible in front helps, removing even more body panels would just make it look very silly and not like a rock crawler. i choose the diesel engine because it gives a lot of torque and combined with the heavy flywheel you can have slow and controlled revs. then i choose the heavy duty frame because its heavier than the standard frame which helps lower center of gravity which means less flipping over. i constructed the gear ratio in this way so that you can just floor it up most hills because the wheels just spin that slow, yes giving even less throttle input sometimes helps but barely because it never catches traction again, atleast it doesnt on this ~50° slope so flooring it with the current gear settings helps it more than going slower. (so basically the grip is the biggest issue here)

but in the end i highly believe its the suspension settings as i have been able to recieve better and worse results by just various different suspension settings

 

Short wheelbase and huge tires is always a recipe for rolling. Also I believe all the crawler tires use the same grip settings, so if you are purely wanting vertical performance put on smaller tires, lower the ride height, or use a longer wheelbase chassis.
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Also like what phivalive said, the bouncing is purely too much throttle. Slowing down lets the tires find grip

 

i want to maximize the build on this chassis and giving less throttle comes with the consequences of worse grip, from my testing smaller tires dont help and just give less grip

 

If you don't want to change anything about the parts you have installed, you may be able to find some improvements by messing with the rebound and compression damping in the front. You may be able to find some inspiration by looking at rock bouncer builds, which I don't know a ton about. But I do think you'll find the biggest gain in performance by changing up your driving technique.