Spent 6 1/2 hours yesterday driving back from my job to home in a snow storm. Conditions weren't too bad when it was solid snow floor the sections that had been plowed and had a 50/50 mix of packed snow and bare pavement were a little sketchy. It was my first drive in snow out side of driving around town since buying this truck. I spent most of the drive in 4 auto and in some spots switched to 4 high. When I was looking over the manual, I didn't see anything about maximum speed while in 4 wheel drive. I kept it under 50 the entire time since that was the cut off in my tundra. What is top speed while 4wd is engaged? another related question, Whats the difference between 4 auto and 4 high?

 

any speed, you could bounce off the speed limiter in 4x4 all day long.

AUTO 4x4 can be used on ANY road surface including dry road as it does not engage the front until the rear spins.

4x4 HIGH to be used on slippery conditions, it is shift on the fly and has no speed restrictions, even if the manual has something i can testify you can hit triple digits without issue year after year.

 

I don't know the real answer from a technical perspective but I also think there is no limit. But like you, I tend to not cruise over 50 mph because,

1. That is how I was taught from a young age.
2. It is my natural comfort limit if roads are packed with snow to the point I want 4WD constantly.
3. I will speed up to pass somebody. It's not a rule I can't break.

Obviously I could drive faster in a straight line because that takes hardly any skill at all. My driving speed on slick roads is based on having a reasonable stopping distance in case of the unknown.

 

In a 2wd truck, the engine puts power into the transmission, and that powers the driveshaft.

In a 4wd truck, the engine puts power into the transmission, which puts power into a transfer case. From there it powers the rear drive shaft all the
time. The front drive shaft, which is also powered by the
transfer case, is engaged only if you put it into 4wd.

This has been done with gears or chain drive, so both driveshafts are
"geared" together and turning at the same speed, with no slippage.
This causes a problem when a wheel wants to go at a different speed, like when you're turning, and you're not on a surface, like snow, that allows slippage.

I've had 4 4x4 trucks, and this is the only one without a published speed limit.

AWD doesn't use this "geared" function of the transfer case; it uses a separate function involving clutches.

In the AWD, or AUTO mode, if you have such a transfer case installed,
driving in AUTO is actually RWD, but the clutches put a bit of pressure
on the front drive shaft. If rear wheel slippage is detected, the clutches engage fully in a nano second, and now your front drive shaft is powered.
I guess it only stays engaged until the slippage problem ends.

I've used mine a lot in the winter, and can tell no difference using it, or
putting it into 4wd. However, if I feel I needed to be in 4wd all the time, I'd select that. The "Old School" attitude as some of you put it.

Some AWD cars operate this same way.
As opposed to Suburu, Audi and others, that power both driveshafts
all the time. And that's my long winded answer to a short question.

 

I figure once I hit about 55mph the road is either good enough I can be in 2wd or I am going too fast if 4wd is still needed.

Had a previous SD that I forgot to take out of 4wd while in the field and it was up to well over 65 on the highway before I caught it.

 

it might just be the roads here, since we dont salt or slow down. but switching into 2wd on the highway here is a very big gamble. first time you give it some gas going around a slight curve, up hill..ect and that back end breaks loose on glare ice/snow covered highway at 70mph you'll be lucky if you only end up in the ditch. i've seen it way to many times and its the reason my trucks stay locked in 4x4 unless there is pure dry pavement.

 

65MPH? In that? Apparently, Alaskans are insane

 

65, 70 mph every day for 6 months out of the year.

 

I drive as fast as conditions allow. 4WD or not, if I need to be in 4WD to begin with I'm not going to be racing like the INDY 500. Thing to remember is that drive train is great for starting and keeping traction but not for stopping. Sue me for the PSA but thats my $.02
Annoys me to no end people that go out racing around thinking they are invincible because there is a 4x4 sticker on the side of their vehicle. I know that a percentage of people know how to drive in the snow(would count most of you all, especially alaskan who has to live in it most of the year LOL) but there is a greater percentage of the random joe that don't (look in the ditches to find them lol). I like my family and I still living/breathing. End rant LOL

But to answer your question there is no limit/cuttoff technically as the others have said on these trucks. Its as fast as you can keep it on the road.

 

Agree'd! thats why i have studded snow tires on 6 months out of the year helps greatly in the turning and stopping and general traction department! biggest thing is paying attention to road conditions, other drivers and your own actions.

 

And Thats Why I included you in the people that know wth they are doing bud lol. Amen on the paying attention to the conditions both in and outside the car.

 

i saw that i get crap on the forums for driving fast but i've never (knock on wood) been in a ditch or lost it in the winter (i have had some issues with keeping the corvette well handled but thats more a horsepower issue). you get a pretty good feeling of traction when your on ice half the year and you know where the line is and when you cross it.

 

Agreed. Normally if you do it enough you get a handle for it but some people don't ROFL. And in regards to the corvette....it can be squirly even its not icy LOL.

 

yeah not being used to the power on a beautiful summer day i ended up doing a 360 in the middle of the road luckily no traffic and no curb shots just scared the hell out of me

 

I did about 99 MPH in 4x4 in the 1/4 mile at the drag strip and ran a 13.5