It's kind of hard to tell from that image how deep you are, but I start to become concerned when the mud goes over the hubs. To me, that depth means that mud ingress is possible in the swivels, brakes and diffs. I'm not sure where the alternator is on a Rangie, but that would be a concern once you get a little higher...heh as well as ingress into the body.
Just make sure you hose off well after each journey into the sticky stuff and inspect your fluids for any possible water contamination.
It depends on the suspension, tires and vehicle speed. You're gonna kick up a large bonnet wake at 30 mph, that you won't kick up at 2-3 mph.
If you don't have the axle/diff breather kit installed, Don't go higher than halfway on the hubs. If you do have that installed, you can get into about 2 feet before the rad fan starts spraying water all over the engine electrics.
Well, assuming that you have axle and tranny breathers and keep a bow wake up going as deep as the hood should be feasible...but god help you if you stop...I don't think those EFI engines take well to ingesting water...
I'd suggest unbolting the fan prior to a deep wading like that...also seal everything electrical up as well as you can...Dunno how much of a headache that is on a RRC... :dunno:
Make sure you attach tow straps to your front and rear recovery points prior to entering the mud hole.
Additionally, if you do go that deep, I'd certainly change out all the fluids below there after such an expedition. Grit and bearings don't get along well...
The problem with going "hood deep" is the fan. If you even get into 2' of water, the bottom of the rad fan will be under/in water. It will then "spray" the water all over your engine.
Assuming your engine is in PERFECT order, it should survive this. However, if you have a bad plug wire, loose plug wire, bad distribuor cap or rotor, or ANY KIND of non-weatherproofed electrical connection... BAM instant Electrical short.
If you look under the hood, you'll notice that the air intake opening has it's bottom LOWER that the bottom of the hood. If you go "hood deep", you'll be sucking water into the intake system. VERY BAD. Unless you install an intake "snorkel" and then test it with soapy water to verify you have no air leaks... Stick to 2' of water or less.
If/When you install an axle/diff/crankcase breather extension kit, route it to the snorkle, or some other "high" point on the vehicle.
Properly modified, you can drive into water OVER hood high, but unless you want to go to some extremes with modifications (and very few do), I reccomend you stick to the "wading pool" depths.
In a standard RR, middle of the wheel depth is no problem. Top of the wheel and I get miss-fires untill it dries out unless I am able to maintain a bow wave. I have had water splash over the hood on occasions and it hasn't done permanent harm, but try to keep moving when in deep water! Also, remember that the door seals are often not very good.
If you do alot of this sort of thing, keep an eye on the condition of all the lubricants or start modifying breathers etc. Expect everything to wear out much quicker!
I cut the engine as it slid lower. Still soaked the air filter...no water past the filter though, MAF and Plenum were bone dry. The coil and disty were soaked though (2 seconds with a powertank and bingo...)
Many people think the problem lays with the fan when the leccy bits get wet far from it,this theory is a big pile o'crap.
The culprit is the bottom pulley it touches the water picks it up and flings it right on the dizzy long before the fan gets near the water,even when the fan touches the water the fan shroud catches most of the water that it throws about.I made a guard that bolted to the timing chest to deflect the spray from the pulley I have waded to the bottom of the bonnet with this set up with no dizzy protection except years of wd40.Just have look next time your wading just to allay your doubts.