Watertight Drivetrain

I just saw a new GC commercial where they talk about its "watertight drivetrain" and it got me thinking. I wonder what they do to make the drivetrain "watertight." The benefits are obvious. I know that people have been fording water just fine for years without "watertight" drivetrains but I figure if you can do more to keep water out of the drivetrain then why not?

To be honest, I have no idea how much water even gets into the drivetrain when crossing creeks and stuff. Are most axle seals watertight, are certain brands more watertight than others, or are there seals specifically designed to be water tight? And that still leaves the pinions to seal as well. Then there's the transmission. I *think* that the AW4 only vents through the dip stick which is obviously fairly well protected from water. But how can you make all of the input and output shafts on the tranny and transfer case watertight? Special seals or bearings I suppose?

And it seems to me that the flex plate leaves a lot of room for improvement in watertight-ness. I don't plan on parking in any lakes or anything, but I still think it would be nice to have a well sealed drivetrain. Ideas, ho!

How do they define "water tight" ? Water resistant is the best you can hope for.

Raising your axle, transfer case, and transmission vent tubes is always a good idea. No seals are advertised as "watertight" or even water resistant, and all owners manuals and 4x4 guides specify that you should inspect your fluids daily for contamination and change as needed after any water crossings.

I agree. And no, I don't know how they define "watertight." They advertise it as watertight though and to me, watertight is pretty easy to define so I would hope that by watertight, they mean watertight.

I just had a thought. I wonder if you could connect the vent tubes to the crankcase to create a positive pressure in the axles in the hopes of keeping water out. Or would it blow out the diff fluid? Just a thought, I haven't gone too far with the idea.

positive pressure systems were on wwII era jeeps, might wanna look there.

Interesting.

And I just did a quick google search for "grand cherokee watertight" and found some HILARIOUS threads on a Hummer enthusiast forum and a Toyota forum about the new GC.

From the Hummer forum:

Don't know if any of you guys have seen the latest commercial on tv for the Jeep Grand Cherokee, but they are touting its off road capabilities. They say it has a raised air intake, (so does the H3), triple door seals, (not the H3), and a 'water tight' drive train. Anybody know if we have a 'water tight' drive train?

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And:

At the end of the day the Jeep is rated for 20 inches of water, and the H3 is rated for 24.

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:roflmao: They sound like such typical hummer owners, quick to compare lengths lastara. Like "water fording ratings" mean jack squat anyways.

And there's equal retardation from the yoter forum.

I by no means think that the new GC is the supreme off-roader, but I do think that it is a very capable rig compared to what else is out there now days.

I just thought the obvious intimidation was funny.

Careful with how much pressure you put in anything, a little too much and you'll start spitting out lube, more and you will blow out seals.

Thats why its so important to keep the vent lines clean and clear.BTW-the AW4 does have a vent line!

With independent suspension, it shouldn't be hard to have a watertight drivetrain. The seals are totally different on the diff and whatever axles are coming out of them. Plus as long as the breather on the trans is high enough, you won't get water in it.

And yes, its very important to keep your breathers clear. I plugged up the breather on my front diff last year because it was spewing gear oil after my ARB reinstall. On the drive back to our hotel after a long day of wheeling, the front pinion seal blew out on the road and I instantly lost all the oil in the front diff. Luckily I had the truck/trailer at the hotel and was able to pop the seal right back in.

I've got to think that a seal that keeps grease/oil in, will generally keep water out. I'm a firm believer that raising vent tubes and checking fluids frequently (especially after water crossings) is all that is needed. "Water tight" seems to be more hype than practical application.

Milford Cubicle II said:

Interesting.

And I just did a quick google search for "grand cherokee watertight" and found some HILARIOUS threads on a Hummer enthusiast forum and a Toyota forum about the new GC.

From the Hummer forum:

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Haha what a bunch of turds. It just reminds me how theres 2 groups of people: The ones who rely on the capability and design of their vehicle from the factory who don't know shit about offroading. Then the ones who don't give a shit about the capability and design of their vehicle from the factory and just build it to what is nessecary.

Oh and I like the guy who says they designed the Hummer door seals over the GC triple seals to flood the cabin so you don't float away crossing a river.
If you need to take on that much water, you shouldn't be crossing the river. Especially since your gonna destroy all the fancy electronics in your brand new H3 anyway.

Super mud said:

Oh and I like the guy who says they designed the Hummer door seals over the GC triple seals to flood the cabin so you don't float away crossing a river.

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LOL correct. It takes Hummer level stupidity to rely on flooding your interior to keep from being sent down the river :laugh2:

Ok, so from what I'm gathering so far is that the "watertight-ness" of the new GC is most likely mostly hype since I can't find crap about it anywhere, including on Jeep's website. Not only can I not find details, their own website doesn't even mention it; not that I can find anyways.

Oh well, that doesn't mean we can't rehash (or hash) the subject anyways.

So other than raising the vent lines on the diffs, tranny, and transfer case, is there anything to do about the input/output shafts/yokes? Or do the bearings create enough of a seal to keep water out as long as you stay moving? Same goes for the axle seals.

Also, sealing all the electrical connectors with dielectric is a good idea. I think the weather pack connectors do a good job of keeping water out, but I don't think that they keep moisture out and therefore will eventually corrode. This is probably a good idea regardless of whether or not you plan on getting into water, if nothing else just to keep them from corroding so fast.

Keeping greasable u-joints well greased should take care of that part of the drivetrain right? Same for the slip-yokes?

Of course there's the intake issue, which I'm sure most of us are familiar with. Either cowl it or snorkel it. To me, a cowl intake is the way to go. I'll never be in water up to my cowl and if I am then I'm most likely having much bigger issues to deal with anyways.

Then there's the EVAP system and I know little to nothing about it. I know it controls fuel vapors... that's about it. Is it a closed system or does it vent? And if it vents can you just relocate the vent just like the tranny/transfer case/diff vents?

I found waterproof axle seals from superior. And waterproof u-joints that don't rely on greasing and regreasing from JE Reel. They're surprisingly affordable too, but I don't know how well they'd hold up compared to, let's say 760 spicers.

That's all I got ATM. Anyone with first hand experience with either crossing deep water or water in the drivetrain care to chime in?

Yea I think the watertight is just a bunch a hype or a fancy saying for "We raised the breather lines to 20 inches!" Really why would anyone dare take a brand new GC offroad anyway? You wouldn't get very far before dragging that plastic bumper on something or scratching the fancy paint. I guess like someone said it will make someone buy it for the fact they can brag how it's built for offroading when they'll never even leave pavement like most rubicon owners.

Anyway I've had one problem with water so far and that's getting into my d35 with a short breather line and some muffed up seals from machining some spacers (which failed) for the bearing and seal when I did my disc brake swap (87 d35 tappered bearings) and led to catasrophic failure coming back from PA which I was in water up to the top of my flares.
I've been up to my doors multiple times which I've only leaked water in once from sitting in it for like 10min. Plus it's bedlined so I shopvaced it right out. I'm about to pull my new 8.8 to regear and see if I've been getting water in through a seal that's already bad. Thats my only real worry considering u joints are easy to replace and with the extra outer seals for the open end tubes on the d30 I shouldn't worry about water getting throgh all the way. But i'm still learning and maybe someone here has a longer experiance than 1.5 years on me.

it was a d35... it did you a favor by committing suicide by drowning!

I would love to see a h3 float. It would be funny to see a 2.5 ton turd float down the river.:laugh3: I could see it as a submarine not a boat.

Well lipped seals are designed to keep oil in not water out, you would want a seal facing both directions. But the leak rate is probably small enough that occasional water seeping in will evaporated once you start driving around.

There are some good aftermarket axle seals that might help. But that will only work for the diff well not even the pinion seal or hub bearings.
You can always try marine grade grease a little better against water.

For me I just try to stay out of the water.