How fast can you safely drive in 4wd?

[The Phoenician]

I've had several 4wd vehicles over the years and they safely drive with all 4 wheels pulling at different speeds. My Tacoma can shift into 4wd while moving and I think I can safely drive it up to 60 mph. I've not done half that speed in my 62 because I don't want to break it.

So my question is, what's the top speed our 6x series are rated for while in 4wd?

 

[HemiAlex]

I’ve done 60 in 4hi. It wasn’t terrifying and I didn’t die.

 

[The Phoenician]

I’ve done 60 in 4hi. It wasn’t terrifying and I didn’t die.

Mine is SOA on 37s, i guess I should have mentioned that. Not sure if it makes a difference.

 

[RockDoc]

As fast as the 62 will go. I would engage and disengage the front output lots winter highway driving in the Canadian prairies (with hubs staying locked). I'd just let off the throttle when I did it to ensure all 4 wheels were coasting (and turning same speed) as it kicked in and out.

 

[Hojack]

I’ve gone at least 55 on snow packed highways going skiing and snowboarding. If they’re was dry pavement I’d disengage 4H and go to 2H and then back to 4H on the snow pack. Wet slushy snow is a totally different story than dry snow. Now I can’t wait for winter... thanks Mike

 

[HemiAlex]

Mine is SOA on 37s, i guess I should have mentioned that. Not sure if it makes a difference.

Stabile is stable.
I was only concerned about the t case moving quickly, but it’s fresh and it’s lived at 3k for days in 4LO without issue.

 

[The Phoenician]

Stabile is stable.
I was only concerned about the t case moving quickly, but it’s fresh and it’s lived at 3k for days in 4LO without issue.

4 lo, I can do all day long. I feel like it's Gonna come apart in hi speeds.

 

[Mark W]

In or out of 4 wheel drive does not affect how fast you can drive your Cruiser. Personally I have run extended periods of 75+ mph in 4 wheel drive in '40s '55s, '60s and '62s and '80s. The limit is dictated by road conditions and the state of all the various systems in the rig. Not by being in 4 wheel drive or not.

Mark...

 

[The Phoenician]

Here's my issue. It's not a big deal at slow speeds or when crawling. But you can feel it when going faster.

The front doesn't have that issue.

Wondering if a double cardan drive shaft will fix it.

I've also had the drive shaft installed the other way, same issue.

 

[Hojack]

4WD or 2WD if that’s the rear drive shaft you think you’d notice that regardless. Only if the front had that would you notice in 4WD and not 2WD.
I’m sure a DC joint is you answer

 

[The Phoenician]

4WD or 2WD if that’s the rear drive shaft you think you’d notice that regardless. Only if the front had that would you notice in 4WD and not 2WD.
I’m sure a DC joint is you answer

It's the front.

 

[Hojack]

It's the front.

Then DC joint that.
I had a DC put on mine.

 

[cruiserpilot]

Double Cardon might do it and with a balancing wouldn’t hurt.

 

[Hojack]

DC joint at the Tcase

Front of driveshaft

 

[The Phoenician]

View attachment 2006973
DC joint at the Tcase
View attachment 2006974
Front of driveshaft

View attachment 2006980

I don't suppose you have the measurements of that drive shaft handy? thinking of ordering one from Tom Woods, unless you have a better suggestion

 

[OSS]

I coulda sworn that I read in some Toyota FJ60 handbook or something to NOT drive in 4WD (locked up) over 50 mph on pavement. On a dirt trail or snowy road it doesn't matter cuz the tires can slip when too much torsion builds up, but on dry asphalt, the tires can't slip at all especially with high traction AT tires. The slight difference in rotation of the front & rear wheels will build up an incredible torsion force on the driveline and transfer case gears when going fast on pavement.
That's why Toyota built the 80 series with full time 4WD.

The worst is driving in the winter on mountain highways on pavement that'll occasionally have black ice. You'll need 4WD for the ice, but keeping it in 4WD on the high traction dry part of the pavement is an invitation to creating extremely high binding pressures between the two axles. You can feel it when the axles bind up from differential torsion caused by driving in 4WD on dry pavement — the car doesn't coast normally and doesn't feel right. It feels like it has constipation. It feels like the brakes are dragging or something.

The rule of thumb that served me well is don't drive over 50 mph with 4WD active and never use it on pavement unless there's obvious ice & snow on the route. And the second that dry pavement looks permanent, get the hell outta 4WD.

On dry dirt roads (not trails) 4WD is never really needed when driving at speed. None of the Baja 1000 racers are 4wd vehicles.

 

[brownbear]

On slippery roads, like snow covered I see no issue going 60-70 mph.

I've driven my 60 at 60 in winter roads.

Shifting in and out thou I do not do more than coasting at lets say 20 mph max.

 

[The Phoenician]

I coulda sworn that I read in some Toyota FJ60 handbook or something to NOT drive in 4WD (locked up) over 50 mph on pavement. On a dirt trail it doesn't matter cuz the tires can slip when too much torsion builds up, but on asphalt, the tires can't slip at all especially with high traction AT tires. The slight difference in rotation of the front & rear wheels will build up an incredible torsion force on the driveline and transfer case gears when going fast on pavement.
That's why Toyota built the 80 series with full time 4WD.

The worst is driving in the winter on mountain highways on pavement that'll occasionally have black ice. You'll need 4WD for the ice, but keeping it in 4WD on the high traction dry part of the pavement is an invitation to creating extremely high binding pressures between the two axles. You can feel it when the axles bind up from differential torsion caused by driving in 4WD on dry pavement — the car doesn't coast normally and doesn't feel right. It feels like it has constipation. It feels like the brakes are dragging or something.

The rule of thumb that served me well is don't drive over 50 mph with 4WD active and never use it on pavement unless there's obvious ice & snow on the route. And the second that dry pavement looks permanent, get the hell outta 4WD

I agree, old 4wd especially are good for dirt roads. For my 2017 tacoma I think 60mph is the limit they suggest.

 

[brownbear]

I coulda sworn that I read in some Toyota FJ60 handbook or something to NOT drive in 4WD (locked up) over 50 mph on pavement. On a dirt trail it doesn't matter cuz the tires can slip when too much torsion builds up, but on asphalt, the tires can't slip at all especially with high traction AT tires. The slight difference in rotation of the front & rear wheels will build up an incredible torsion force on the driveline and transfer case gears when going fast on pavement.

I know what you mean. I would not want to drive on too much bare pavement in 4wd. Even with my Ford 4x4, same thing.

But honestly it's just some more wear and tear, it's harder on the transfer case and driveshafts etc. But unless you are on a curvy road or in a parking lots a typical road is very little deviations on the steering wheel. I may run in 4wd and just not worry about the extra wear.

My T-case is due to be rebuilt now. After 16 years of ownership and now it has 200k miles on it. It was used lots on bare pavement too.

 

[Hojack]

I don't suppose you have the measurements of that drive shaft handy? thinking of ordering one from Tom Woods, unless you have a better suggestion

I could but all of our swaps are custom. Motor and axle placement are different. Find a driveline shop. I took mine there and gave him measurements from both faces of the flanges and he set me up.