4-High (4WD) in heavy rain on-road?

Curious if there is any actual consensus on utilizing 4Hi when freeway driving at or below 50mph in heavy rain / pooling? Aside from the “you shouldn’t be driving at all” … yes, of course, but sometimes duty calls.

With the recent and forecasted heavy rains in the N. California / Bay Area it occurred to me driving home this evening that it may be worth re-asking a question that has surely been pondered on this forum before (though a search surfaced nothing).

 

I would think it would be fine if you don’t have too many sharp turns.
Even though it’s raining the pavement would still probably cause binding of the front driveline.

 

Yes, and I’ve always been super hesitant to engage 4WD on pavement under any condition for just that reason - the fear of forgetting and the potential outcome.

 

The conditions you are describing would be best navigated in 2WD w/all the nannies on. If you're not getting adequate rolling friction, you are either driving too fast for conditions, or you are running the wrong tires. On these trucks, the factory Michelin LTX AT2s are some of the best tires for wet pavement conditions.

 

The KM2’s that I’m running are probably among the worst for wet slippery roadways - slow and easy, and lots of buffer for stopping are paramount.

 

I have before. I wouldn't worry about the binding, people act like the tundra has a glass differential or CVs and can't handle a little binding. Plus if you're driving faster than a crawl then the binding is effectively a non issue anyways.

My perspective is when things have the potential for hairy, 4WD is the go to. If I need to get on the gas I want to make sure the front is pulling me where I need to go.

 

Little binding or not, it’s not good or beneficial on your diff.

Thinking you need 4WD for rain is wrong. Going too fast in deep rain with puddles gives you the chance to hydroplane but there isn’t any other worries. don’t overthink it.

 

I've never done it personally; I don't think it would be as harmful as driving in 4WD on dry pavement.

But me personally, I would put a little bit of weight over the rear axle whether you intend to drive in 2WD or 4WD. I've always put weight over the rear axle in all of my trucks in significant rain and keep it in 2WD. First rain after a dry spell is pretty bad here due to the oil. Weight along with conscious driving has never made me feel like I need 4WD in the rain - now AWD would be nice, but that's another story.

Me too -- I'm usually in 4WD before I need it in other cases.

 

Another vote for 2Hi here. It's not clear to me why you'd want to be in 4Hi in that scenario.

 

I've never felt the need for 4wd in rain except when I had KO2's on my Tacoma. Taking off on a hill was an adventure once they got half worn, but normal driving was fine, it was just getting moving. As long as you have decent tires, and aren't driving too fast you should be fine in 2wd.

 

A couple weeks ago I was in 4HI going through trails.
The trail ended unexpectedly and there was a paved road with a cop sitting there. No other cars around so I was like WTF???

I wasn't doing anything “wrong” but who likes to be slowed down by cops.

I could see on map that the next off-road trail was 1/2 a mile up the paved road.
So instead of putting in 2WD and risking a suspiciously long delay I just impulsively drove forward and kept it in 4HI. There’s no other cars around but I still get it up to 50 mph bc that was the speed limit.

I sure hope that was OK to do but if I do it again I’m gonna take the time to put it back in 2WD and slow roll it.

 

another vote for 2HI and keep it 40-50mph based on visibility (highway) less in town obviously.

 

Never had the need for 4WD in any rain storm…

Another vote for 2WD.

In a couple of ice/rain storms but that was only with BfGoodrich and Goodyear tires. Many other lesser sized brands handily outperform those two brand nowadays in the rain and inclement weather…

 

You could have shifted back to 2WD without stopping. You can shift in motion between 2WD and 4HI below a certain speed (I think it's 50 or 55 MPH) without any worries. You only have to stop and go to neutral if you are engaging/disengaging 4LO.

 

Is it really suspicious to stop at the end of a trail long enough to shift back to 2Hi? All you have to do is turn the knob while you're rolling slowly.

 

My only advice is to drive for the particular conditions you are in. This goes for weather, traffic, wildlife, road conditions, whatever.

We're you having trouble getting enough traction to motivate the truck?? If not, I would say 4wd was unnecessary for your conditions.

4wd will not help you to turn or stop any better or faster. It will only be useful to get you going in a situation with limited traction.

If you were slipping and sliding while in motion, you are either driving too fast or need to look at more appropriate tires.

I hope this helps.

 

Unnecessary

 

If you think you need 4wd in the rain, what you really need is different tires and a slower speed.

 

I've driven the Bifmobile through some serious cow-patty floater monsoon storms here in Central Texas and never had to put it in 4WD. Like everybody has said, drive for the conditions. Slow down, give yourself extra room to stop, and you'll be fine.

 

It will be fine, just don't do sharp turns with it.
I drive on wet pavement in 4wd, to get the 10 miles in 4wd the manual talks about, when I can't get out to the woods. Have done this with every Toyota I have owned and never had an issue. Again just watch the turns. I anticipate the turns and take it out of 4wd before hand.

 

How many times have you driven a 2wd car in the rain and said, “Boy, I could really use 4wd right now.” Never.

 

Tell that to Mustang drivers.

 

I have driven 4wd trucks in standard rain for 20 years and never felt the need to be out of 4wd. I know some people like auto 4wd for rain as an extra insurance against slippage on wet pavement and I knew a dude who used to drive his truck in rain in 4hi at all times. If I remember right I believe he said that was mainly for high speed highway driving without sharp turns and he avoided it in stop and go.

More power to them. I have always done fine keeping good tires on the vehicle and driving within its limits. One of the hand full of times I ever did a Deep crossing in a flood, 4wd came in handy because there was a scenario where I felt the truck get light and getting whichever tire still had firm contact digging in helped move me forward again. For plain old Slick pavement, my truck stays in 2wd. I am in an F150 now, some versions have 4wd auto. I would have liked to have had that option, but did not end up snagging a model with it. I would have only wanted it so my wife could flip the switch and leave it without going back and fourth depending on terrain when she has to get to work in a blizzard. Other than that the truck would have stayed in 2wd.

 

Maybe so but with some main differences, Cars are usually front wheel drive which helps a lot with control of the vehicle as your pulling as opposed to pushing. Second cars have their weight distributed of over the drive axle, or in the case of rear wheel drive cars, more evenly distributed between the axle as opposed to empty bed truck.

The traction and safety of having all 4 wheels driven is undisputed. One of the reasons so many cars have all-wheel drive or some system of the sort. There is nothing wrong with putting your 4 wheel drive on in heavy rain conditions on the highway. In California we are getting massive rain storms right now. The 4 wheel drive system on the tundra can be activated while rolling up to 60 MPH. The reason is for added traction in these HI-gher speed situations that may not be extreme but benefit from the added stability and traction of 4 wheel drive. Personally if I'm driving on the freeway or a highway and there is standing water, I use 4 Hi. There are no turns sharp enough on a modern highway that would cause binding. If I'm on city streets I don't use it.

You paid for the feature, no need to sandbag yourself, if you have the tools, use them. Ok ready for the haters

 

The hell is wrong with some of you????
You wipe before you poop too???

standard rain?

if you need 4wd EVEN in 6 inches of standing water to get going then you need to get off the bald ass tires you’re on or learn how to drive a vehicle.

 

99.99% of accidents in the rain is caused by poor visibility, lack of braking ability, hydroplaning, and driving too damn fast. None of which 4wd is helping in any of those cases. If anything, 4wd will give false confidence to a driver and make him drive faster than he should. Only time it might help in the rain is when you’re driving aggressively on twisty roads. 4wd in the rain on a relatively straight freeway will do nothing for you other than wear out components faster and give you worse mpgs.

 

The ONLY situation where I could possibly see myself switching a truck into 4wd in the rain, is in heavily traveled, desert type communities during the first rain in months.

Definitely experienced some crazy slick roads in Vegas while rocking a rental Navigator. That damn vehicle still wouldn't let you do anything fun, even with the nannies turned off. We were relegated to reverse J-turns, but I digress.

...All about tires and driving for the conditions.

Seems like some people might have a trouble distinguishing between typical 4WD systems and AWD systems... I'll just try not to buy THEIR truck in another 10 years.