4WD speed question

[SigPig94]

Hi all:
I was told by the dealership that I should NOT exceed 35mph when I have my 4Runner in 4WD, specifically 4H….just curious if this sounds accurate because what about highway driving in heavy snow/bad conditions/etc???
Thx for any advice and other tips on 4WD usage!

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[Jakethewhippet1]

https://www.4runner6g.com/forum/threads/4h-4-high-max-speed.7739/#post-92991

 

[MikeD]

Hi all:
I was told by the dealership that I should NOT exceed 35mph when I have my 4Runner in 4WD, specifically 4H….just curious if this sounds accurate because what about highway driving in heavy snow/bad conditions/etc???
Thx for any advice and other tips on 4WD usage!

The BS that some dealers are dishing out is getting me annoyed. Ask them for a reference in the owners' manual. There they will find this (p408 of Hybrid manual) (and consistent with what Nodak said in the linked thread):

"Shifting from “4H” to “2H”​

1 Reduce vehicle speed to less than 62 mph (100 km/h).​

2 Push and turn the front-wheel drive control switch to “2H”."​

It would be hard to "reduce vehicle speed to less than 62 if you are supposed to max out at 35. UGGH

 

[brumey]

I think reading the owner manuals should be a requirement for service techs and advisors. The lack of knowledge is shocking to me. I feel I know more that the advisor at each interaction. Not just Toyota, other big name brands too.

 

[127.0.0.1]

Hi all:
I was told by the dealership that I should NOT exceed 35mph when I have my 4Runner in 4WD, specifically 4H….just curious if this sounds accurate because what about highway driving in heavy snow/bad conditions/etc???
Thx for any advice and other tips on 4WD usage!

4L is where you should never exceed 35mph

you'd be strangling that motor and transmission
running it at 'surface street' speeds in 4L

heck in 4L keep it under 20...[my 4L speeds are basically 0-4mph]

 

[Lamuncha]

I am not sure 4 WD at highway speed in bad conditions gives you any advantage over 2 WD, especially if it isn't independent. In fact it could be a disadvantage as the wheels are more or less locked to each other.
If you are trying to motivate through a foot of heavy snow - yes probably would be an advantage, but you likely are not going 60.

 

[127.0.0.1]

I am not sure 4 WD at highway speed in bad conditions gives you any advantage over 2 WD, especially if it isn't independent. In fact it could be a disadvantage as the wheels are more or less locked to each other.
If you are trying to motivate through a foot of heavy snow - yes probably would be an advantage, but you likely are not going 60.

true..
it is an advantage in AWD where there is a center diff and you
can keep it in AWD in turns with no issues, it helps pull you along
w/o slip when pavement is less than stellar or conditions suffer

not much of an advantage with PT 4wd, it's not really doing good
at high speeds and it's scrubbing the tires and making a lot of transfer case heat
while pulling you thru turns. so yeah it works in the salad but also has inherent slip
where AWD doesn't

 

[Nodak]

to piggyback on /dev NULL's post

typical awd systems just employ the brakes to simulate 4wd and most will not let you perma lock the center diff. most will disengage after 25-30 mph (in toyota's at least). most of the time they are fwd vehicle and either shift to 60/40 bias or there abouts.

i havent really read up on the new 26 rav4 and see how the hybrid awd works now or if it still follows conventional wisdom on fwd with brakes to simulate awd. havent had a unibody awd vehicle since our rav4 v6. the subie legacy 3.6R i had was a true awd with a perma lockable center diff before they went cvt on them.

only those BoF vehicles with a FT4WD system will let you lock the center diff permanently (limited/platinum 4R, 5th gen limited, sequoia, land cruiser 250 and 200/300 series, tacoma limited)

 

[127.0.0.1]

to piggyback on /dev NULL's post

typical awd systems just employ the brakes to simulate 4wd and most will not let you perma lock the center diff. most will disengage after 25-30 mph (in toyota's at least). most of the time they are fwd vehicle and either shift to 60/40 bias or there abouts.

i havent really read up on the new 26 rav4 and see how the hybrid awd works now or if it still follows conventional wisdom on fwd with brakes to simulate awd. havent had a unibody awd vehicle since our rav4 v6. the subie legacy 3.6R i had was a true awd with a perma lockable center diff before they went cvt on them.

only those BoF vehicles with a FT4WD system will let you lock the center diff permanently (limited/platinum 4R, 5th gen limited, sequoia, land cruiser 250 and 200/300 series, tacoma limited)

rav4 AWD is simple and works great

97% the time it's FWD.
on a snowy day it's gonna use AWD (add rear torque) a bunch

rear wheels on open diff kick in via MGR (motor generator rear)
and provide motive power and torque when slip is detected
or when you accelerate from a stop. rear wheels almost never
provide torque when moving along at speed (unless slip is detected)

yes it's open diff and brake controlled like all Toyota VSC
to provide limited slip

MGR provides about 54HP max
where RAV4 hybrid overall HP is 236

 

[bakutheleo]

Everyone here is basically correct, no max speed once engaged. However, you should not be using it on-road anyway, as it should only be used when the tires can slip a bit--in particular on curves. If you turn a curve in 4WD one of the tires has to slip a little--if it cannot easily, it will anyway and put torque on the differential.

And yes, I believe all that is in the manual. Interesting the wrong info from dealers.

 

[Joestac]

Didn't want to start a whole new thread for this but I was reading the manual and noticed this note too which I thought was interesting.

"Four-wheel drive usage frequency You should drive in four-wheel drive for at least 10 miles (16 km) each month. This will assure that the front drive components are lubricated." Page 417

 

[127.0.0.1]

Didn't want to start a whole new thread for this but I was reading the manual and noticed this note too which I thought was interesting.

"Four-wheel drive usage frequency You should drive in four-wheel drive for at least 10 miles (16 km) each month. This will assure that the front drive components are lubricated." Page 417

this helps the multiple servos which operate in the front and transfer case to get
some exercise and not get stuck or bound up with old grease, and also spins the
front shaft ujoint to keep them fairly exercised as well.

if you never ever use 4wd and some day you need it after 8 winters
you may find it won't engage smartly, or not at all.

it will engage and disengage faster and cleaner
if you use it now and again to loosen things up

 

[Joestac]

this helps the multiple servos which operate in the front and transfer case to get
some exercise and not get stuck or bound up with old grease, and also spins the
front shaft ujoint to keep them fairly exercised as well.

if you never ever use 4wd and some day you need it after 8 winters
you may find it won't engage smartly, or not at all.

I didn't necessarily need another excuse to go get dirty, but I'll take it.

 

[NotApplicable]

this helps the multiple servos which operate in the front and transfer case to get
some exercise and not get stuck or bound up with old grease, and also spins the
front shaft ujoint to keep them fairly exercised as well.

if you never ever use 4wd and some day you need it after 8 winters
you may find it won't engage smartly, or not at all.

it will engage and disengage faster and cleaner
if you use it now and again to loosen things up

I'm sure it does, but 10 mi/mo in climates that only have inclement weather for part of the year is difficult to guarantee!

 

[127.0.0.1]

just switch it on when you are going straight and back to 2wd
when you need to turn. it can be for a few tenths of a mile and
if so, just do that a handful of times here and there

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