Tacoma 4WD Systems & Drivetrain Technologies Explained by Toyota

[Sner]

Not sure if this has made it to the forum yet. Great video from Toyota on the 4WD systems. Seems many are buying Tacomas and posting about vibrations on dry pavement as they are simply not familiar with what they bought.

Good on Toyota for educating customers and potential buyers.

Toyota's 4WD Systems & Drivetrain Technologies Explained | Toyota

00:00 Introduction to Toyota's 4WD System
00:18 Toyota Part-Time 4WD and Full-Time 4WD
00:33 Toyota Rear-Wheel Drive Default
01:19 How to activate Toyota part-time 4WD
03:36 Toyota Full-Time 4WD Overview

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[Goriders]

If you crank the wheel every 4WD system I have driven isn’t happy. Straight away and regular turns are typically fine.

 

[Miqie]

You are supposed to engage 4WD for 10 miles each month. I ususally do this if it's raining and drive a straight road.

 

[bitflogger]

You are supposed to engage 4WD for 10 miles each month. I ususally do this if it's raining and drive a straight road.

That is an important point. Even when Toyota had a mechanical lever vs turning the knob one could have the engagement or disengage be stuck. When my 4Runner was 12+ years old it could require a bumpy road if I did not do that often.

 

[Mini2nut]

Thanks for sharing. I always love to read anything technical regarding the 4th Gen Tacoma’s.

 

[dholmq]

Hi. I have been struggling with the choice between buying the Part Time 4wd Tacoma Limited VS. Full Time 4wd Hybrid Limited system. I live on the Oregon Coast and often travel in slick areas during the spring/winter. I have had many trucks and SUV's with an automatic 4wd option that seem to work well in those conditions. The only reason I would want the hybrid is the full time 4wd. Does it really matter or am I overthinking it?

 

[Sner]

Hi. I have been struggling with the choice between buying the Part Time 4wd Tacoma Limited VS. Full Time 4wd Hybrid Limited system. I live on the Oregon Coast and often travel in slick areas during the spring/winter. I have had many trucks and SUV's with an automatic 4wd option that seem to work well in those conditions. The only reason I would want the hybrid is the full time 4wd. Does it really matter or am I overthinking it?

NO! I think you are smart!! More educated than most who buy these trucks! There sure is something to be said for having the auto mode. And yes Limited gets it. Set it and forget it, let the system do it's thing. Surprised Toyota only does it on the limited, and not the premium trims as well. So many trucks have an auto setting now a days.

 

[Ron]

Hi. I have been struggling with the choice between buying the Part Time 4wd Tacoma Limited VS. Full Time 4wd Hybrid Limited system. I live on the Oregon Coast and often travel in slick areas during the spring/winter. I have had many trucks and SUV's with an automatic 4wd option that seem to work well in those conditions. The only reason I would want the hybrid is the full time 4wd. Does it really matter or am I overthinking it?

I wanted fulltime 4wd with the offroad suspension and locking rear diff. And no chrome.

Hybrid limited won.
No regrets but i haven't been offroad or thru a winter yet.

 

[BLtheP]

Not sure if this has made it to the forum yet. Great video from Toyota on the 4WD systems. Seems many are buying Tacomas and posting about vibrations on dry pavement as they are simply not familiar with what they bought.

Good on Toyota for educating customers and potential buyers.

Toyota's 4WD Systems & Drivetrain Technologies Explained | Toyota

00:00 Introduction to Toyota's 4WD System
00:18 Toyota Part-Time 4WD and Full-Time 4WD
00:33 Toyota Rear-Wheel Drive Default
01:19 How to activate Toyota part-time 4WD
03:36 Toyota Full-Time 4WD Overview

You keep peddling this argument that the 4x4 can't handle dry pavement, but that is simply not true. If you are driving in a straight line, there should not be any vibrations whatsoever in 4WD. Dry pavement will not hurt anything in minor turns, and certainly not in a straight line. Vibrations don't occur from the pavement itself. If there are vibrations, either it's a bad driveshaft or drivetrain component, or poorly designed driveshaft geometry.

Even if you do drive on pavement and make a sharp turn (dumb), you will be hard pressed to actually cause a problem from doing so. The diffs, CVs, t-case, etc are not made of glass. Clearly not recommended to do so and anyone should actively avoid doing so, but none of this is why anyone has vibes.

 

[Sner]

You keep peddling this argument that the 4x4 can't handle dry pavement, but that is simply not true. If you are driving in a straight line, there should not be any vibrations whatsoever in 4WD. Dry pavement will not hurt anything in minor turns, and certainly not in a straight line. Vibrations don't occur from the pavement itself. If there are vibrations, either it's a bad driveshaft or drivetrain component, or poorly designed driveshaft geometry.

Even if you do drive on pavement and make a sharp turn (dumb), you will be hard pressed to actually cause a problem from doing so. The diffs, CVs, t-case, etc are not made of glass. Clearly not recommended to do so and anyone should actively avoid doing so, but none of this is why anyone has vibes.

Well you do you. It’s not what the video says. Part time 4WD should not be used on dry pavement. Period. You should review the video at the 3:00 minute mark. Pretty evident from Toyotas video they disagree with you. heres some other videos and video saying the same thing. You should also review how a differential works, how a central differential works, and how a transfer case works to better understand.

Here is the take away - and my point. If you walk into your Toyota dealer with your Tacoma that has the part time 4WD system and tell them you are getting vibrations on dry pavement in 4WD the first thing they well you is “don’t do that” and would not entertain your concern any further. The could dealers would likely refer you to the video I posted from Toyota. It’s the first thing a technician would do to diagnose a vibration complaint On A part time 4WD system. Is the customer driving in 4WD on dry roads “yes….. don’t look any further. “No” axles, drive shaft, wheels, tires … check other stuff. But full stop on diagnosing any vibrations on dry pavement if it’s a part time 4WD and in 4WD on dry pavement.

How am I so versed in this? Well first, I’m a certified automotive technician, I’m also an automotive teacher - teaching transmission and driveline systems for the last 21 years (Amongst other systems) A rule I teach students when they are diagnosing part time 4WD systems and a customer comes in with complaint of vibrations in 4WD on dry pavement - put it back 2WD and if there are No vibrations, send the customer on their way. If a customer comes in with vibrations on a part time 4WD system on loose gravel or snow - that’s another story.

Clearly there’s a problem af Toyotas service counters from owners or they wouldn’t have gone through the effort and investment in making the video explaining 4WD… appears some still will question.

 

[BLtheP]

You should also review how a differential works, how a central differential works, and how a transfer case works to better understand.

Look man, I know how all of them work. I have rebuilt numerous transfer cases, regeared, rebuilt stock diffs, etc. Here in a week or so I will be ripping out the ADD in my 3rd gen to replace with the full time FJ non-ADD tube so I have a more reliable 4x4 engagement (where only the tcase has to shift now and not both). I’m not some beginner to automotive mechanics who is just arguing about something I don’t know about just for the sake of arguing, and you’re not teaching me anything I don’t already know. As I’ve said, I don’t encourage 4wd use in the road. What I am saying is doing so isn’t going to grenade the drivetrain like some seem to believe. There have been too many accidental “my wife drove it in 4x4 for 3 hours and I just found out!” posts where the truck turns out perfectly fine for that to be the case.

The problem with the logic here about the specific vibration problems is that pavement use itself doesn’t create the vibrations. 4Hi is allowed to shift at up to 62 mph and can go up to governed speeds once it’s shifted. That means above 100 mph. If you have vibrations at any speed in 4x4, you’re going to have them both offroad and on road. The vibrations are inherent and need to be solved. The fact that the owner found the vibes on pavement and the dealer won’t help at that point means it’s a cop-out excuse. Even though you’re not supposed to drive 4x4 on pavement, that doesn’t mean you should have vibes if you do and drive in a straight line. The vibes are a bigger issue like an unbalanced driveshaft or something and need to be addressed, regardless of where the owner was driving it to find the vibes. I’m sure they probably will feel the vibes in gravel too but they will be harder to feel on an uneven surface. Pavement would make it a lot easier to determine if something is buzzing and potentially damaging pinion bearings, seals, etc in the front diff.

I can assure you, I can put my 4wd in 4Hi, go hit the highway up to 90 mph in a straight line and it is perfectly smooth as glass. I have no reason to do that since part time is not meant for the road, but I absolutely can, and anybody else should be able to without vibes.

This like telling the dentist your tooth hurts and rather them looking at the tooth and fixing it, they tell you to quit drinking soda and send you on your way. You probably should quit drinking soda for the sake of your tooth, but you have a bigger problem that needs attention too.

 

[Sner]

Look man, I know how all of them work. I have rebuilt numerous transfer cases, regeared, rebuilt stock diffs, etc. Here in a week or so I will be ripping out the ADD in my 3rd gen to replace with the full time FJ non-ADD tube so I have a more reliable 4x4 engagement (where only the tcase has to shift now and not both). I’m not some beginner to automotive mechanics who is just arguing about something I don’t know about just for the sake of arguing, and you’re not teaching me anything I don’t already know. As I’ve said, I don’t encourage 4wd use in the road. What I am saying is doing so isn’t going to grenade the drivetrain like some seem to believe. There have been too many accidental “my wife drove it in 4x4 for 3 hours and I just found out!” posts where the truck turns out perfectly fine for that to be the case.

The problem with the logic here about the specific vibration problems is that pavement use itself doesn’t create the vibrations. 4Hi is allowed to shift at up to 62 mph and can go up to governed speeds once it’s shifted. That means above 100 mph. If you have vibrations at any speed in 4x4, you’re going to have them both offroad and on road. The vibrations are inherent and need to be solved. The fact that the owner found the vibes on pavement and the dealer won’t help at that point means it’s a cop-out excuse. Even though you’re not supposed to drive 4x4 on pavement, that doesn’t mean you should have vibes if you do and drive in a straight line. The vibes are a bigger issue like an unbalanced driveshaft or something and need to be addressed, regardless of where the owner was driving it to find the vibes. I’m sure they probably will feel the vibes in gravel too but they will be harder to feel on an uneven surface. Pavement would make it a lot easier to determine if something is buzzing and potentially damaging pinion bearings, seals, etc in the front diff.

I can assure you, I can put my 4wd in 4Hi, go hit the highway up to 90 mph in a straight line and it is perfectly smooth as glass. I have no reason to do that since part time is not meant for the road, but I absolutely can, and anybody else should be able to without vibes.

This like telling the dentist your tooth hurts and rather them looking at the tooth and fixing it, they tell you to quit drinking soda and send you on your way. You probably should quit drinking soda for the sake of your tooth, but you have a bigger problem that needs attention too.

Here’s the thing. There’s more people who have bought these sorts of vehicles with zero knowledge of how their 4WD system works, than there are of legit 4WD vibrations complaints at the dealerships service counter.

#1 problem always for 4WD vibrations on dry pavement is not from driving in a straight line, it’s people having zero understanding of what they bought and use of it. I can agree that all else being perfect, straight line driving - okay should be fine. BUT my experience says most 4WD vibrations on pavement complaints are due to stupid things usually due to not knowing what sort of system they bought.

A case study example, how about a customer who has a part time 4WD system who never rotates their tires. Has bald tires on one axle and lots of tread on tires on other axle, comes in complaining about vibrations in 4WD only felt on dry pavement in 4WD… anywhere else, loose gravel no vibration

How about a customer who comes in with a part time 4WD system same thing vibration in 4WD on pavement - decided to put on aftermarket wheels and put two different sizes on front to back.

How about the guy who decided to put the aftermarket lift kit on, only gets vibration in 4WD on dry pavement

In the perfect world, brand new part time 4WD truck, drive off the lot, hit a straight road put into 4WD high it should take it. Go around a corner - no it won’t take it. But ANYTIME after it’s brand new and a customer comes in for vibration in 4WD on dry pavement and statistically there’s nothing wrong with the vehicle, it’s something customer is doing wrong, wrong tires, wrong lift, went around a corner, pulled into a parking spot Etc. Almost never does a customer come in for this one complaint where’s a legit issue to look at ESPECIALLY on a new truck. If there was anything to look at it would have other symptoms and be felt at other times.

vibrates 4WD on straight road, new truck with part time 4WD - if there’s something else (legit) other than ignorant customer there‘d be vibrations felt in other conditions. Dealers and technicians just know it. Hence why Toyota likely published the video. My point all needs to be perfect/stock to drive on dry pavement in 4WD in a straight line to not get a vibration. In this discussion, Tacoma’s are one of the most modded trucks. Heck too much weight in the bed, put it in 4WD on dry pavement, unwanted vibration. Take the weight out, vibration goes away. things need to be perfect to do it, it’s the reason we always say no 4WD on dry pavement with a part time system. It’s because unless all is perfect, you’ll get vibrations - and technicians know that there are way to many variables and most customers when they come in with the complaint it’s because wasn’t perfect conditions to do it. Again at that point if there was something to look at for a vibration customer would have concerns at other times.

 

[Vidman]

All correct

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