Engineering Explained - FT4WD vs PT4WD (4Runner Part-Time 4WD vs. Land Cruiser's Full-Time 4WD)

[Scott2373]

If you ever wondered what the difference is, here ya go!



Description:

Is Full-Time or Part-Time 4WD Better? Toyota 4Runner/Tacoma vs Land Cruiser 4WD!
Deep dive into how these 4WD systems work, and the advantages of each.

The Toyota Land Cruiser and the Toyota 4Runner are both highly capable off-road vehicles, but, which one has the better four-wheel-drive system? All Land Cruisers come with Full-Time 4WD, where as most 4Runners come with Part-Time 4WD. In this video we’ll explain exactly how both systems work, what the advantages are of each, and ultimately discuss which system is superior. The Toyota Tacoma has the same 4WD system as the 4Runner, so anything in this video that applies to the 4Runner also applies to the Tacoma.

Once we have a general understanding of how transfer cases work, we'll dive into the following questions:
How does the low range gear selection work?
How does the full-time system create a 40/60 torque split?
How does the Torsen center differential work?
How does the part-time system select 4WD?

 

[zachavm]

Long story short, the advantages of a part-time system over a full-time system are negligible. The only real advantage as far as the 4Runner is concerned is that Toyota doesn't offer many off-road features on the full-time system. No rear-locking diff, No sway bar disconnect, No MTS, and no crawl control.

Meanwhile, the full-time 4WD has massive advantages from being able to be used on the road. There is significant performance improvement in bad weather.

 

[Clodydeloady]

Here in Canada 6 months of winter AWD is almost necessary if you commute to work every day!

 

[juan bernardo cañon parra]

Buenos días, saludos desde COlombia, ambas camionetas son buenas maquinas, pero si es mas para el off road, prefiero la 4 runner, así la prado diga que sirve para el off road, pero la 4 runner es mas imponente, espero pronto tener la mia en Colombia, la usaré para ir a los sitios donde casi nadie va a compartir la palabra de DIOS, como lo es en los llanos orientales. DIOS los bendiga,

 

[Scott2373]

Here in Canada 6 months of winter AWD is almost necessary if you commute to work every day!

I lived in Western New York for my first 48 years. The Buffalo / Rochester / Syracuse area is one of the snowiest areas in the US, thanks to Lake Erie and Lake Ontario. 108.4 in./year average between the 3 cities. I'm sure AWD is great (I've never owned an AWD vehicle) in those conditions, but there is no substitute for good driving skills. I can't tell you how many Subaru's and 4x4's, even snowplows, that I've seen slid off the road, in the ditch. Your vehicle's ability is only as good as how you drive it.

 

[yvr4runner]

I'm curious. I do understand that part-time 4WD does not have center differential so it does not allows wheels to turn at different speeds when making corners.

Does this mean, with a part-time 4WD 4runner, I should 'never' drive on 4HI even when roads are slippery due to heavy rain/snow? Or, does it just mean to avoid any sharp corners? I guess what I'm trying to understand is how much 'stress/binding' the system can handle without causing damage?

 

[MrOzMan]

I'm curious. I do understand that part-time 4WD does not have center differential so it does not allows wheels to turn at different speeds when making corners.

Does this mean, with a part-time 4WD 4runner, I should 'never' drive on 4HI even when roads are slippery due to heavy rain/snow? Or, does it just mean to avoid any sharp corners? I guess what I'm trying to understand is how much 'stress/binding' the system can handle without causing damage?

If the rear wheels don’t spin in 2wd, I say there’s probably too much traction for 4x4 (part time). But if it’s questionable, and safety is the priority, then cautiously use 4x4.

 

[Scott2373]

I'm curious. I do understand that part-time 4WD does not have center differential so it does not allows wheels to turn at different speeds when making corners.

Does this mean, with a part-time 4WD 4runner, I should 'never' drive on 4HI even when roads are slippery due to heavy rain/snow? Or, does it just mean to avoid any sharp corners? I guess what I'm trying to understand is how much 'stress/binding' the system can handle without causing damage?

You can safely use PT4WD on snowy roads, as long as there is some slippage. I would strongly suggest NOT using 4x4 on wet (from rain) roads, however. I used to live in Western NY and sometimes used 4x4 when it got particularly bad out and the plows hadn't gone through yet.

 

[zachavm]

I'm curious. I do understand that part-time 4WD does not have center differential so it does not allows wheels to turn at different speeds when making corners.

Does this mean, with a part-time 4WD 4runner, I should 'never' drive on 4HI even when roads are slippery due to heavy rain/snow? Or, does it just mean to avoid any sharp corners? I guess what I'm trying to understand is how much 'stress/binding' the system can handle without causing damage?

Here is what the manual says about 4 High:

Use this for driving only on tracks that permit the tires slide, like off-road, icy or snow-covered roads. This position provides greater traction than two-wheel drive.

Personally I would want to be pretty confident there would not be random places where I suddenly had all wheels have firm traction. So I wouldn't use it unless snow was for sure on the entire road. All it takes is one strong torque of your system the wrong way to cause thousands in damages.

 

[Mrknowitall]

The only place where part-time 4wd is problematic is in a dry parking lot or such place where you'd turn the wheel more than ~1/2 turn each direction. where I live, that would leave you CONSTANTLY shifting in and out of 4wd for 2-3 months of the year. That said, I find it unforgivable that a Michigan-based engineering team didn't push for more full-time availability on other trims, for ALL of the North America specific models.

 

[zachavm]

The only place where part-time 4wd is problematic is in a dry parking lot or such place where you'd turn the wheel more than ~1/2 turn each direction. where I live, that would leave you CONSTANTLY shifting in and out of 4wd for 2-3 months of the year. That said, I find it unforgivable that a Michigan-based engineering team didn't push for more full-time availability on other trims, for ALL of the North America specific models.

I thought the design team was based in Texas. Regardless, I agree. Toyota should be putting this system on WAY more trims and vehicles. Only having it on the Limited hybrid is just stupid. I honestly feel like it should be on EVERY 4WD Tacoma. The cost difference is probably not that bad. I would be surprised if it was more than 50 bucks since it is just a different transfer case.

The only reason (besides cheaping out) that I can think of for them not to do it is customer knowledge. Most buyers would be familiar with traditional part-time systems, but many likely won't understand a full-time system. They may just equate it to AWD systems used in crossovers and assume it is substandard.

Side note: Bias against AWD systems is stupid and largely built on ignorance IMHO. There are some that don't transfer much power to the back or distribute power well overall, but in general they can be just as good or even better for many uses.

 

[jnsplace]

It's on the Platinum too.

It could be that fine line of where does this vehicle fit? It's not a SUV (where AWD makes sense), it's also not a truck (where choosing between 2X or 4x is the standard).

At the end of the day, I believe it's because of the category of people where this vehicle tends to get sold to.

People that trick it out, go off roading, camping or what not. Those people want to have the control of switching.

 

[kobyneal]

Long story short, the advantages of a part-time system over a full-time system are negligible. The only real advantage as far as the 4Runner is concerned is that Toyota doesn't offer many off-road features on the full-time system. No rear-locking diff, No sway bar disconnect, No MTS, and no crawl control.

Meanwhile, the full-time 4WD has massive advantages from being able to be used on the road. There is significant performance improvement in bad weather.

Knowing more info now would you agree that the LC with the full time system offers all of the off road items mentioned above (locking diff, mts, crawl control, and sway disconnect) on 2/3 models? Just making sure I’m not confused as I know lots of information has come out since this post thanks!

 

[Azimuth]

The flagship Land Cruiser has been full-time 4WD since the 80 series, introduced in 1990. I think the only reason they don't have it on all trims of the 4Runner is to push people to pay more and buy the LC250. The LC250 (a.k.a Prado) sold abroad has FT 4WD as well from what I gather.

 

[BG1]

Long story short, the advantages of a part-time system over a full-time system are negligible. The only real advantage as far as the 4Runner is concerned is that Toyota doesn't offer many off-road features on the full-time system. No rear-locking diff, No sway bar disconnect, No MTS, and no crawl control.

Meanwhile, the full-time 4WD has massive advantages from being able to be used on the road. There is significant performance improvement in bad weather.

Watched an amazing U tube on full time 4WD vs AWD. I have no knowledge of why Part time AWD may be better for Off Road, that is not my interest, but for the average user, Full time 4WD is superior especially IF there is no loss in MPG.

We have a RAV4 Platinum and 4Runner Sport both with AWD.
- The RAV has to be put AWD and will switch out of it at about 25-30 nonsensical for wet / slippery conditions.
-The 4 Runner AWD is manual selection also but as it has no active differential, so AWD on semi dry roads is a no no, It will judder like crazy in turns since the curve needed by each axle is different. No good for rain after a dry spell or if road conditions are variable in the hills of N. NJ So you get stuck with Rear WD most of the time.
- Full time 4WD has the Jorsen or similar differential that allows the front /rear axles and wheels to rotate at different speeds and as well as changes front to rear ratio so give best traction in all road conditions.
As you say, clearly the best for adverse or good ROAD conditions, maybe not OR.

I had the fulltime 4WD on my BMW 330i and my Subaru Outback V6 (not the viscus coupling CVT version) - they were really solid drives in all weather conditions.

It's a shame the fulltime 4WD is not offered on the TRD Sport