4 Wheel drive in rain

Anyone drive in 4 wheel drive in the rain on city streets? Is that still too much tension on the driveline with not enough slip in the wheels?
Any advisement from Toyota against it?
I've been driving an AWD in the rain lately and it has quite the grip. Wondering if I can do that in my Tacoma and not damage anything.

 

No.

i have a manual j shifter i could change it from 4hi to 2hi before tuening but its not worth it, just drive slower

 

Wouldn't recommend it. Turning on grippy pavement will bind and eventually break something in the powertrain.

 

I live in the city, and getting the opportunity to exercise the 4wd the recommended 10kms every month would be difficult if I didn't engage it in the rain. I have a fairly straight stretch of road to travel to and from work. Some mild bends but generally straight. I engage 4wd on rainy days regularly. 4 years of ownership and I have never had an issue. Just don't take any hard turns and you will be fine. These Toyota's are pretty robust.

 

Section 4.5 of you manual clearly covers this stating:
"...driving only on tracks that permit tire slide, like off road, icy or snow covered roads."
Two pages later under the heading of WARNING they clearly caution against it.

This is a compact pick up with a part time 4 wheel drive system not a AWD car with a center differential system.
If you feel the need for 4 wheel drive in the rain in the city you are driving way too fast.

 

I thought we drove Toyotas…

 

I engage my 4wd in the rain to get the miles in, just don't do any full lock turns. I choose straight roads with few turns. I will turn it off if a tight turn is required then back on. I'll choose an access road and go into straight line 4LO for a few blocks back and forth a few times also. The wet road will allow for some slip.

 

Toyotas aren't invincible, especially when you abuse them.

 

The OP isn't talking about limited exercising of the system, he was specific about driving in the city and using the 4 wheel drive for increased grip in the rain.

 

AWD is designed for running all the time. 4WD is not. Lots of factors play into the amount of grip you have, such as weight properties of the vehicle, tires, etc.

As they say here in the winter climates: 4 wheel drive does not mean 4 wheel stop. If you're driving along and having trouble with grip or are hydroplaning, you need to slow down. Also consider what type of tires you're running.

 

AWD isn't the same as 4wd. An AWD vehicle will send power to all 4 wheels and allow them to turn at different speeds. 4wd is an older, much less complex system that sends 50% of the power to the front axle and 50% to the rear. It is trying to make all 4 wheels turn at the same speed. Which is the best system for more challenging off-road conditions or deep snow. Far from ideal on wet pavement or light snow. If you're trying to get moving on an incline in the rain and are spinning the rear wheels I don't have an issue with using 4X4 just long enough to get moving. A boat ramp is the perfect example, but it could be on a city street too.

If you're in 4x4 on wet pavement it doesn't help and could make things worse. When you go around a corner at least one of your wheels, maybe 2, is going to spin slightly on the pavement. Which is not good. Instead of helping, you're forcing at least one tire to lose traction with the pavement. An AWD vehicle will keep power to all 4 wheels in that corner without any of them spinning.

If you're driving on wet pavement in 4X4 you are less likely to do any damage than on dry pavement, but I still don't advise it. And the less cornering you do, the less damage you do. But IMO the risk isn't worth the reward. If you get distracted, forget you're in 4x4 and start making hard turns on dry pavement you could be looking at an expensive repair. And yes, I've had to pay that bill in the past.

Virtually everyone has forgotten to disengage 4X4 and gotten back on pavement before they realized it. Unless you make a really sharp turn in high traction area you don't see catastrophic failure. But you are over stressing components that will eventually fail sooner than they should. The less you overstress parts, the longer they last.

 

And, if you have a locker, using it when passing for extra speed........No, no to all of the bad advice. 4wd is not for when it rains.

 

I don't do it on city streets but I do it all the time on highways. I did it in my 2007 and I do it in my 2014. I have ~300K miles of driving total across both my 2nd-Gen Tacoma's doing what you are asking about on interstates - not city driving. I watch my gas mileage carefully and I don't see a meaningful loss in MPG and I have had nothing but reliable and trouble free driving from both trucks.

For obvious reasons, I also would never recommend 4W drive Low on highways. I don't know if it typical of all 2nd-Gens but I also slow down to 50 MPH to engage and disengage 4W drive. This easy to do as I typically engage and disengage on the acceleration and deacceleration ramps. I seem to remember reading in the owners manual that is advised. I do it because the above 50 the system does not seem to engage/disengage reliabliy.

 

This probably wouldn't apply to the Tacoma.

I see some part time 4WD trucks that have setting for wet and or slippery conditions. That engages the 4hi. That are not AWD trucks.

I don't know if those settings are any different than engaging 4hi separately.

I gues that would depend on the how the transfer case operates.

 

Side comment here:

I always laugh at people who think they are going to break their 4WD if they engage it on dry pavement. Watch some videos of people wheeling in Moab, that sandpaper texture rock makes the tires bark as they bind and release... If you are breaking driveline components from the odd 4wd pavement experience you have an unhealthy driveline that is past due for repair.
On that same note, you will increase wear if you run 4wd on the dry constantly. Lots of examples online of people doing this for months and years and having lots of odd things wear out. But occasional use, even while tightly turning on dry pavement should be fine, not something to freak out about. These trucks are pretty resilient.


Moab is awesome, if you like wheeling, it should not be missed.

Edit: bolded months and years. [it takes some serious abuse is my point]

 

I think it more comes down to your second paragraph and undue stress on components. If you're wheeling you're generally tossing that out the window and are also more likely to encounter slippage.

 

Agree with you although, I don't laugh; to each his own. There is the risk of increasing the wear but I also "think" it depends a lot on maintenance and driving habits. The reason I say this if you watch you tac when you go from 2-wheel to 4-wheel Hi it bascially doen't move. If you watch ScanGauge it basically verifies what you are seeing on the tac. As long as your driving habits "on the highway" don't create a situation where the passenger side tires are racing the driver sider tires around a corner (or vice versa) you are not creating abnormal wear and tear.

If you are driving in 4-wheel drive at 80 miles and hour for extended periods of time, although I don't have a way to verify heat build-up I would expect it may become an issue. I also can't tell you at what speed heat can become an issue. I can tell you that up to 55 to 60 mph I'm not concerned but I do change from and rear transfer case oil more often than most.

What I laugh at is when people share information and don't realize what they are doing is sharing facts "the way they see and interpret them". This human behavior is NOT sharing facts, it is sharing opinions. Unless someone has recorded data to share I'm thinking the real facts are limited to:

- if 4 wheel drive increases RPM you could be stressing the engine and other parts of the drive line.
- if 4 wheel drive makes the driver and passenger tires race each other around corners you are stressing the drive line and for the most part you can hear and feel it; anything electomechancial that sounds and feels different is not a bad indicator of electromechanical stress. The exception, of course, is heat which if you can't always have access to feel and at times you may not always be able to hear.
- if speed and maneuvers can create unnecessary heat and stress on electromechanical parts in the drive line.
- if you adhere to some fundamental principles and insert a bit more preventative maintenance into you routine you are likely to extend the life of your drive line even if there is more wear and tear than I may think.
- I don't know whether Toyota designed the Tacoma to run on straight dry pavement but as long I adhere to the above facts I only know I have 300K miles on the sum of two trucks with no adverse wear and tear.

If I don't make it 250K miles in my 2014 I'll let you know I'm drinking my own bath water which by definition I'm an idiot.

 

Better tires

 

I engage mine all the time in the rain on pavement and have for decades on previous Ford, Mazda, and Toyota 4WDs. Never any problems at all. The forces on the drivetrain when you are actually 4x4ing are 100X what they are on rainy pavement.

It behooves one to be sensible and not do it on a slalom track, but a straight stretch of rainy pavement will mild curves will not create catastrophic wind-up in the drivetrain. Just click it on for a few miles when it crosses you mind. Click it off if you see a sharp curve coming. The more you operate it the better.

 

Please define a sharp curve........

Curve on an On ramp or highway.
Curve at a street intersection.
Curve turning into a parking space.

Speed related?