River/water crossing in the back country - water leak?

I'm looking to take my 2024 4Runner into the back country with a few other folks. They warned me that there may be some light river crossings, but nothing too crazy. Water levels may come up to the floor board height or maybe slightly higher.

If this is the case, could water leak into the truck?
Would be a pain trying to clean it all up after. Even worse, would hate for the water splash to make its way into the engine bay which could cause possible damage?

 

Take a boat or find a bridge. Unless you’re willing to risk problems in the future.

 

At a minimum you’d want to have proper diff breathers installed. Stock breathers may cause water to be drawn into the differentials. Not expensive or difficult to do.

Without proper breathers, after your trip you should plan on replacing the front/rear differential gear oil and replace the axle seals. You don’t want water sloshing around in the differentials.

Breathers are cheaper.

 

Front breathers are pretty high up as I remember, so you’re mostly worried about the rear…which isn’t even that big of an issue unless you spend a lot of time submerged or go through water that is cold.

If you have an upcoming service, just have your diff oil changed then. It’s much cheaper at a dealer than local stand alone places, ironically enough.

The only thing you really should worry about is making sure you don’t go to a level where the air intake is submerged.

Also, don’t splash. Just go in nice and easy, and keep a steady speed.

 

If you're just going through the water and you're not parking in the water, then the seals on the doors are adequate to keep water intrusion out. I wouldn't want to linger in any water deeper than 2/3 up the wheels but going through it is no issue.

 

That isn't deep enough to worry about anything but the splash. Splashing may get water into the engine bay, but not because of the water depth. Drive through the water under 10 mph and you'll be fine. The faster you go, the more splash. Go slow and steady.

 

Splashing, especially with mud, is how you end up with a clogged alternator or other sensors.

Ask me how I learned this lesson!

 

As long as you don’t crash into the water on entry, and as long as you maintain a slow steady speed, those depths are probably fine. Staying in the pocket behind the bow wave will help reduce the height of the water around the vehicle. Do the breather mod on the rear diff.

The trick is maintaining your pace. But if you get stuck half way across…at those depths, you might be screwed.

If nobody is sure about the underwater conditions, it’s probably be best if you and your buds are immediately ready help pull a vehicle at the first sign of trouble. That means having tow straps connected and at the ready on your vehicle, and somebody else willing to jump in the water to grab the strap and connect to a recovery vehicle that’s ready to go on shore. That will also require that you trust whoever may be pulling you out, because recoveries can be dangerous if you don’t know what you’re doing.

 

Typically the door seals will hold. The doors themselves take in water (through the drain holes). So your maximum fording depth is roughly the height of your door speakers.

As others say, reroute your rear diff breather and avoid splashing. Pack a spare air filter along with the other parts and tools you normally take on wheeling trips.

 

legend

 

I did this last March. One of a dozen-ish crossings. I do have the rear breather mod. It's a 10 min job. No issues at all. As you can see the water is to the bottom of the headlights. That's 37" deep. Keep the splashing to a minimum.

 

Forget about your floor boards. You need to make sure you don’t hydro lock the engine. And as others have said the diff breathers. Also remember 1 gallon of moving water has 6 pounds of force. Not trying to ruin your adventure but getting your floor boards wet would be my last concern.

 

...And don't forget to make absolutely sure that your skirts/splash shields are 100% intact if you decide to ford that high.

 

That’s an awesome picture. Do you have a snorkel? Anything you need to do to prevent hydro locking the engine? That’s such a cool picture. Nice job.

 

Not to derail the thread, but where did you run your diff breather ends? I'll be doing mine in the next couple of months and I'm debating going up to the engine bay vs the tail lights or gas nozzle. 10 min sounds like a quick job staying near the back

 

Close!

A gallon of water weighs 8lbs - actually a little more. A pint weighs around a pound.

 

Thanks...I don't think I will be going that deep...but that looks pretty wicked!

 

Thanks... That is what I was hoping for. Hoping the door seals will hold. The water level will not be too high, it could reach the floorboard level at worst is what I am being told.
I intend to go in and out as smoothly as possible. Not looking to do any Dukes of Hazzard's stuff thru the water.

 

Thanks & well noted. I was told about this from my friends as well. Good callout!

 

Looking at the ARB breathers right now...

By the way...how many breathers do I need for a 2024 5th Gen? Also seeing a Youtube video where they talk about the 2 diff breathers, transfer case & transmission breather? (ugh...).
looks like I'm going down a rabbit hole....

 

If you haven’t noticed, videos often exist to convince you that you need to spend a stupid amount of money on things.

Just remember that while mods produce some benefits, the cost/benefit analysis may not pay off, especially if you think about the potential for issues with your mods.

Your front diff already has a breather placed high enough that you aren’t going to have an issue there before you get another issue.

I forget what’s going on with the transmission, but look at the instructions - if you are modifying your transmission in any way, you need to seriously ask yourself if preventing all the stories you’ve heard of transmission failures are worth the potential for a denied warranty claim.

And if you haven’t heard a bunch of stories, then perhaps it’s a solution in search of a problem.

 

You'll be fine. Of the approximately one million water crossings* I've done I've never had an issue. I also don't / didn't do the breather mod; again, for short duration submersion you'll be fine. Don't overthink it and just do it.

*probably slightly higher than actual number

https://youtu.be/-fVw9N4T6aI?si=jkhUH4Gn4WThBLF2

 

airbag computer under center console. once you get water level inside cab on a floor, vehicle totaled. when water gets once inside frame, life expectancy of the vehicle dwindles down.

 

The frame has probably a hundred places for water ingress (and egress) and water gets in there (and out) under normal operation like driving in the rain. I would make a similar argument to yours in that once you start the truck the first time the life expectancy goes down, too....

 

No, I do not have a snorkel.

I ran the hose up the gas filler tube as far as it would go and zip tied it. Leave a 4-6" loop near the breather so the hose doesn't get pulled out under full droop. Here's the breather stud I used. Then get any 1/4" gas line hose.
https://www.toyotapartsdeal.com/oem/toyota~union~no~4~90404-51026.html

 

Anyone else read that? There's nothing you need to do OP, but have a good time.

 

Thanks, I've got hose from the ARB kit but need to see if I need anything else. I'll be running a breather for the locker too so will probably need a "T" at the very least.

 

Yeah, with a locker you'll need a "T". I don't have a locker and forgot about it.

This guy did the breather mod the right way. (i.e. more $$)
https://www.youtube.com/watch?v=1MFW8YK9dx0

 

So you're saying 1 gallon of water exerts 6lb force regardless of how fast it is moving? I find that interesting. If you put a gallon of water on a scale, it weighs 8.3lb...

 

I think it makes more sense to say a gallon of water weighs around 8 pounds, at rest, meaning it’s to say it’s a dense liquid (which is non-compressible). Because of this, you need to enter it slowly enough to allow the water to flow around the vehicle. If you hit water at high speed, it will act like a dense, massive solid for a split second which can easily break plastics and bend metal. Once in the water, going too fast can also bend/break things through hydraulic forces. Point being, the combination of water and speed can break things.