Driving on 4H 4wd

[08 Hilux Surf]

What is the max speed driving on 4H 4wd? I heard the max speed on 4H for the new 5th generation 4R is 60mph. I live in Seattle which "rains a lot" and I often used to drive my old '08 4R SE on a wet surface freeway up to 75mph and never had any issues while owning the 4R. Of course the main use on 4H was dirt and gravel (or snow) roads and would not drive over 55mph.
Please comment if driving over 65mph on a freeway with wet surface may be a problem to the new 5th gen 4R. I got a new '21 TRD Off Road this summer and unfortunately had to give up my 08 4R SE due to high mileage (no issues on 4wd). Appreciate your feedback/comments.

 

[mscot]

I've never gone over 60. If I can go that fast I'm usually safe switching back to 2wd.
The 5th gen does not have an LSD on the front when in 4x4 mode so the front tires can bind.

 

[Ascole]

There’s a handful of threads about this, seems the most recent is this one:

Top speed in 4-High

As a side note; I’m from Seattle and have never felt the need to drive in 4wd on the highway in the rain.
Probably helped I learned to drive there in a 2wd Ford Ranger with bald tires and no weight in the rear.


Sent from my iPhone using Tapatalk

 

[BorotHex]

I don’t understand why one would drive in 4WD on just a wet road.

What’s the objective?

 

[AuSeeker]

I just read what it says in your owner manual...

"H4 (high speed position, four-wheel drive)
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."

I highlighted in red the adverb which is key to what it says you can or can't do. IMHO

It says nothing about how fast...but more importantly it doesn't say wet/rainy roads/tracks, which tells me not to use 4H on just rainy/wet roads because it apparently doesn't allow "tire slide", or at least enough "tire slide" to not damage the 4WD system.

 

[jp.vegas]

The ‘08 4Runner Sport had an all wheel drive mode. You put it in 4 high but don’t lock the center diff, and it can be used on any road at any speed the vehicle is capable of, just like the Limited trim.

None of the 5th gens, besides the always AWD limited, have his capability any longer because there’s not a lockable center diff on the other trims.

4 high in a 5th gen is the same as 4 high locked center in the old 4th gen sport model. You shouldn’t be driving on wet roads with it, only loose or icy surfaces as stated in the manual.

 

[JK47!]

This is good info. Is anyone aware of an actual situation occurring with a Gen5 where driving in H4 improperly has damaged the 4x4 system? Just wondering how much abuse it would take to break something.

 

[RichinRidgewood]

I engage 4H in the rain whenever I think there could be a traction issue. I drive at the appropriate speeds for the conditions. I don't bother if Im driving on slow moving surface streets.

 

[spartacus]

This is good info. Is anyone aware of an actual situation occurring with a Gen5 where driving in H4 improperly has damaged the 4x4 system? Just wondering how much abuse it would take to break something.

Most folks will not knowingly try to abuse or break their 4x4 systems on this forum but then again I might be wrong

 

[JK47!]

Most folks will not knowingly try to abuse or break their 4x4 systems on this forum but then again I might be wrong

I was thinking more along the lines of accidentally leaving it in 4H and driving at excessive speeds on dry pavement and causing damage. Not purposely trying to kill it.

 

[Jetboy]

What is the max speed driving on 4H 4wd? I heard the max speed on 4H for the new 5th generation 4R is 60mph. I live in Seattle which "rains a lot" and I often used to drive my old '08 4R SE on a wet surface freeway up to 75mph and never had any issues while owning the 4R. Of course the main use on 4H was dirt and gravel (or snow) roads and would not drive over 55mph.
Please comment if driving over 65mph on a freeway with wet surface may be a problem to the new 5th gen 4R. I got a new '21 TRD Off Road this summer and unfortunately had to give up my 08 4R SE due to high mileage (no issues on 4wd). Appreciate your feedback/comments.

Max speed is not 60mph for driving in 4hi in the 5th gen. The max speed to shift from 2hi to 4hi is 60mph. The limit is because there's a clutch that engages to bring the non-spinning parts up to speed in the transfer case before the gears mesh. So it has a max engagement speed. Over that speed it just tells you to slow down before it'll engage. Max driving speed in 4hi is 113mph in the 5th gen. I believe that is the same for all models. The Limited version shares the same drive train entirely except the transfer case is awd and it lacks the front passenger side intermediate axle shaft disconnect mechanism. And it also shares the same 113mph speed governor I think.

65mph is no problem in 4hi on wet roads. I wouldn't think twice about 80mph cruising in 4hi. I've done it many times.

Good luck.

 

[08 Hilux Surf]

Thank you for your input/comments. Yes, I agree about the max speed when shifting to 4H from 2H. But I never seem to get a clear answer on the max speed driving on 4H. Furthermore, I get more comments that I shouldn't drive on wet surface. All my other 4WD Toyotas driven in Japan recommended/allowed me to drive 4H on wet, dirt, or snow conditions. Obviously I'm not trying to damage the 4wd on my new TRD OR, but my main purpose of driving in 4H is the "traction" while driving in the rain for "safety purpose". Freeway surface may be smooth, but with rain driving around 60-75mph there are always some slight curves, uneven surface, or small holes, and even possibility of hydroplaning as the amount rain/pour can change constantly... And of course I wouldn't drive 60-75mph in heavy snow either. I get various comments which is a bit confusing but thank you for your comments!

 

[Devbot]

There’s a handful of threads about this, seems the most recent is this one:

Top speed in 4-High

As a side note; I’m from Seattle and have never felt the need to drive in 4wd on the highway in the rain.
Probably helped I learned to drive there in a 2wd Ford Ranger with bald tires and no weight in the rear.


Sent from my iPhone using Tapatalk

Also from the area, yeah this is just absurd :wacko: Only time I use 4WD in the rain is coming up are on the hills in Everett and Seattle in stop-and-go traffic
That's like putting on studded tires on for a frosty morning

 

[Baystate4Runner]

Max driving speed in 4hi is 113mph in the 5th gen. I believe that is the same for all models. The Limited version shares the same drive train entirely except the transfer case is awd and it lacks the front passenger side intermediate axle shaft disconnect mechanism. And it also shares the same 113mph speed governor I think.

Speed gov in 5th Gen models is 118mph and that’s were mine kicks in (speed measured with GPS)

 

[Jakeepoo3]

What is the max speed driving on 4H 4wd? I heard the max speed on 4H for the new 5th generation 4R is 60mph. I live in Seattle which "rains a lot" and I often used to drive my old '08 4R SE on a wet surface freeway up to 75mph and never had any issues while owning the 4R. Of course the main use on 4H was dirt and gravel (or snow) roads and would not drive over 55mph.
Please comment if driving over 65mph on a freeway with wet surface may be a problem to the new 5th gen 4R. I got a new '21 TRD Off Road this summer and unfortunately had to give up my 08 4R SE due to high mileage (no issues on 4wd). Appreciate your feedback/comments.

40 mph

 

[mscot]

40 mph

^ not even remotely correct.

 

[spartacus]

Max speed is not 60mph for driving in 4hi in the 5th gen. The max speed to shift from 2hi to 4hi is 60mph. The limit is because there's a clutch that engages to bring the non-spinning parts up to speed in the transfer case before the gears mesh. So it has a max engagement speed. Over that speed it just tells you to slow down before it'll engage. Max driving speed in 4hi is 113mph in the 5th gen. I believe that is the same for all models. The Limited version shares the same drive train entirely except the transfer case is awd and it lacks the front passenger side intermediate axle shaft disconnect mechanism. And it also shares the same 113mph speed governor I think.

65mph is no problem in 4hi on wet roads. I wouldn't think twice about 80mph cruising in 4hi. I've done it many times.

Good luck.

This is news to me. I believed that the limited awd had a center differential that the part time 4 wheel drive lack. Therefore causing the transfer case to wear out prematurely.

Exclusive to the 4Runner Limited, the full-time 4WD system uses a Torsen® center differential with locking feature and a three-mode, center console-mounted switch. The system uses a 40:60 torque split in most driving situations and alters that in response to slippage. If the front wheels are slipping while the vehicle is turning, the Torsen® differential changes the split to 30:70. If the rear wheels slip while the vehicle is turning, the differential changes to a 53:47 split.

 

[Jetboy]

This is news to me. I believed that the limited awd had a center differential that the part time 4 wheel drive lack. Therefore causing the transfer case to wear out prematurely.

Exclusive to the 4Runner Limited, the full-time 4WD system uses a Torsen® center differential with locking feature and a three-mode, center console-mounted switch. The system uses a 40:60 torque split in most driving situations and alters that in response to slippage. If the front wheels are slipping while the vehicle is turning, the Torsen® differential changes the split to 30:70. If the rear wheels slip while the vehicle is turning, the differential changes to a 53:47 split.

Yes the limited has an AWD transfer case. VF4BM I think. Like I said. I don't think that has any bearing on max speed other than to suggest that there's not a constraint from the front axle system. Presumably going north of 100mph is unlikely to involve tight corners where the center differential would come into play.

 

[Jetboy]

Thank you for your input/comments. Yes, I agree about the max speed when shifting to 4H from 2H. But I never seem to get a clear answer on the max speed driving on 4H. Furthermore, I get more comments that I shouldn't drive on wet surface. All my other 4WD Toyotas driven in Japan recommended/allowed me to drive 4H on wet, dirt, or snow conditions. Obviously I'm not trying to damage the 4wd on my new TRD OR, but my main purpose of driving in 4H is the "traction" while driving in the rain for "safety purpose". Freeway surface may be smooth, but with rain driving around 60-75mph there are always some slight curves, uneven surface, or small holes, and even possibility of hydroplaning as the amount rain/pour can change constantly... And of course I wouldn't drive 60-75mph in heavy snow either. I get various comments which is a bit confusing but thank you for your comments!

There's really nothing you can do to damage it. The system is robust and can handle being driven in 4x4 on dry pavement all you want at any speed it will go. It'll just be uncomfortable on tight corners where it'll bind up. It's possible it could cause some handling issues as well on curvy roads if you're pushing the limits of available traction. But you won't break anything. It takes a lot more stress and abuse off road.

And you won't overheat the 4x4 components at speed.

IMO - toss it in 4hi whenever you want.

I rarely use it on pavement unless it's snowy or icy. The roads where i live don't tend to be all that slippery when wet - or I don't drive fast enough to find the limits. If I'm in doubt, I'll just pop it in 4hi. But I have driven from Salt lake to Moab Utah and back towing my camper in 4hi the entire way mid summer in 100* temps and dry roads. No issues at all. (I had an unknown at the time problem with my front ARB grinding its internal spider gears unless it was in 4wd, but I was a trail guide at a club event so I just ran in 4hi.)

 

[Jetboy]

Speed gov in 5th Gen models is 118mph and that’s were mine kicks in (speed measured with GPS)

That sounds right. Been a while since I tested it. Tires are 118 speed rating so they'd probably match that with the governor.