Exercised my 4wd mode today, heard a slight noice for a sec. Problems or normal?

I strongly advise against doing so. As long as you are not making any turns you lessen the damage. But it simply isn't worth the risk. Find a surface with loose dirt, gravel, sand or even grass even if you're only able to engage 4X4 for a shorter distance.

Making sharp turns and cornering on dry pavement will very likely lead to immediate complete failure. But just because something didn't break today doesn't mean you didn't do damage to the transfer case. The transfer case uses a chain to transfer power to the front wheels as shown in the photo. Even though you don't break something immediately every time you put the chain under stress it stretches. It will eventually stretch enough that the chain will begin slipping on the gears and you'll have to have the transfer case rebuilt or replaced.

 

When you engage 4wd there are two things that happen:

1- the front axle disconnect rejoins the two halves of the front axle
2- the transfer case switches into 4hi

Either item can be in a degree of misalignment, which is why there is sometimes two clunks, sometimes one clunk, and sometimes no clunk. It will be different everytime.

You can run on dry pavement, in 4hi, in a relatively straight direction without issue. Just avoid sharp turns as others have said.

For a while I drove a F250 at work that got stuck in 4Hi. Truck was driven around town for a couple weeks before the actuator circuit was repaired. No big issues other than awful binding in parking lots. That was ten years ago and the truck is still around. Whatever damage we did or didn’t do to the T-case hasn’t killed it.

 

So I once was on a rough road in 4WD and then came on to asphalt. (It was really weird: the path out to a campground was a pretty bad unpaved road and then, deep in the mountains, the campground was paved). I started into a sharp turn and it felt rough. I stopped and got out of 4WD immediately.

Haven't noticed an issue since. How worried should I be?

 

I was in SF about a year ago and took a detour to show my then 3 year old that section of Lombard street that is about five switchbacks. There was a two block long queue up a steep hill as it’s a tourist attraction. I have a stick, so instead of roasting my clutch every time we inched forward, I put it in 4low. When we finally crossed the intersection to descend the switchbacks, I realized I forgot to shift back to 2hi. But it was too late, my wheels were turned and it wouldn’t disengage. So I tried backing up a few times but no-go. I had little choice but to keep going.

About halfway through the first switchback, BANG!, it slammed back to
2 hi. I was really worried I’d grenaded something but it all seems fine for now.

Anyway, back to the relevant conversation....

 

You are saying two different things here. I would agree with your second statement. Using 4wd offroad on anything but graded gravel is going to wear the system.

The reality is that coasting and / or wiggling the steering is sometimes necessary to get in and out of 4Hi. When driving straight on any surface, all components are rotating at the same speed. So, exercising the system on straight dry or wet pavement is perfectly acceptable. Given the few reports of actuator failures, I would go so far to say that excising it on straight dry pavement is probably doing good more than anything else.

Everyone that uses 4wd has accidentally left it on and made a turn onto pavement. It is nothing to worry about unless it is being done all the time.

 

Roller chains do not stretch and people should stop saying that they do. Chains wear. The amount of tension force necessary to actually stretch a roller chain (aka bend the pins) is a couple of orders of magnitude greater than the transfer case housing could ever hope to hold.

 

Thanks man!

 

No problem!

 

Were you completely in 4Hi before you started moving? Was the 4Hi indicator solid or blinking while you were stopped? My guess is it just had a tough time getting in...shouldn't happen but probably not a big deal.

 

Really? That one failed box picture has been making the rounds on every forum for the past eight years. One picture, one failure. If I remember correctly, that is a Jeep Grand Cherokee case and the guy drove it for 60,000 miles or so in 4WD before failure. C'mon man.

 

Exactly. There is no possible way our truck's tires slipping on dry pavement in a turn creates the force required to stretch the chain.

 

My old bosses daughter's Trailblazer actuator failed because she drove it for 4yrs in Auto4x4.

Two data points!

Oh yeah. The dealer quoted more than the thing was worth to fix it.

 

How are you engaging 4wd? I always put it in reverse and roll a few feet before going forward. Makes the 4wd light come on solid. Same for 4low: neutral, select, reverse, go.

 

It's amazing. One picture of one failed case has generated and alarmed tens of thousands of people to discuss this issue. Worse yet, they don't understand so they make shit up and post it!

I'm pretty sure you could put our trucks in 4HI, cut the wheels to full lock and burn through tankfuls of gas and as long as you monitored the case temp you wouldn't fail a thing, other than wearing out your tire.

 

For 4Hi, just flick the knob regardless of situation. Sitting still is usually the most difficult to get a full engagement.

Just a note, though I know this is not specifically what you were talking about, but we don't need to worry about rolling backward for full engagement or disengagement. We don't have that style hubs. Just two dog gears. One in the t case and one on the front right driveshaft.

 

But that doesn’t matter, because someone’s 1984 Chevy once blew out 4wd component when they switched it on doing 45.

 

I just do it out of habit. It always locks in clean and smooth this way.

 

true, and i appreciate that but do a take speed, momentum, and the resulting forces into account. i will turn some miles here and there on the highway if it's wet, but i generally avoid a dry highway or similar due to the risk of emergency maneuvers. do one of those at highway speed in 4H and find out what happens. nothing to be neurotic about, just taking care of your stuff.

 

look man it's really hard to get out and lock the hubs when they're spinning around that fast, plus I might dent the hood when I climb out onto it

 

Just make sure you use the fancy Toyota LF t-case fluid at $80/L. Otherwise it’s ka-blammmo!!!