Your 2017 manual page 89
4WD -
This mode supplies power to the front and rear wheels. Steering will require slightly more effort than with 2WD. This mode is recommended for driving on surfaces with relatively poor traction.
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That last sentence is an answer, sort of. The common man would think, yep that means more traction to help me get out, and you would be correct. But, it also allows the tires to slip independently, even though they are locked together.
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The differential gears are slightly different sizes. The tires, for sure, are different sizes, even when new. And now you tie them together, all to the same driveline, and force them to turn at the same speed. On dry surface, the gears are binding, fighting against each other, there has to be slippage somewhere, and you feel it as vibration. Hopefully you only feel it as slipping of the tires.
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If you are in 4WD, or 4WD Diff Lock, on hard dry surface, pavement is even worse, yes, you will feel it/hear it.
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I know you do not have turf mode, but I already had this diagram made up so....oh well, haha
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ONLY use 4WD, or 4WD Diff Lock, on loose or slippery surfaces. 👍
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edit to add
You joined in 2019, and this is your second post.
WHERE are the pics of your rig?
Come on man post up some pics. We want to see it. hahahaha
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Have a good day