Damage from Tight Turning in 4Hi?

Just out of curiosity .. When I bought my rig, the dealership lady who also drives a Taco, told me she drives hers in 4WD at 60 mph all the time. (This is in Montana on snowy/icy roads however ... Not dry pavement.. So basically just winter time ..)
And then I asked her .. Still at the dealership ... Can you shift in 4WD on the fly? (I still haven't read through 300 pages of owners manual) She said 'I think you can, but I always stop and then put it into 4WD' .. Which is .. Man that's OLD-school... But maybe a 'better safe than sorry' thing..

 

You can shift into 4hi on the fly up to about 60mph (or 62 I guess for 3rd gens). Not going to hurt anything.

Just make sure your wheels aren't slipping when you do it, that can end badly. I shift in/out of 4hi on the fly all the time but I take my foot off the gas when I do.

For shifting into 4lo, you need to be at a stop. Trans in neutral/clutch in if manual, all that good stuff.

 

Nah, Old School is shifting out of 4Hi then driving backwards to unlock the hubs. I still catch myself doing that sometimes.

 

Thank you. Being a geezer, I'm still not used to the shifting stuff on the fly without imagining everything exploding .. LOL!
Oh, the 4W-LO .... I had a 79' Dodge PowerWagon where getting it into 4W-LO required a 4 week class at the local community college, waving a dead-chicken around it, and a whole lot of praying/luck .. LOL!

 

People here:

Wife accidentally drove all over town in 4-Hi. No worries it’s a tough truck

Dealer backed up my truck 10 feet in 4 Hi. Make them buy your truck and get you a new one!

 

LOL!!! EXACTLY! (79' Powerwagon ... That was the only way to do it.) And even then it might have taken 2-3 tries before you weren't grinding the gears to death in the transfer case, right? LOL!

 

old school is parked in neutral, wrestling with the t case shifter, getting out and locking the hubs. in -40.

 

huh. you guys are right, I always read the manual as to keep the speed in 4hi under 62 mph... never really considered that once in 4hi you can go faster, but that is the wording in there.

but as someone else also said, I guess if conditions require 4wd, you probably shouldn't be going that fast anyway (generally speaking)

 

open differentials are your friend.

 

Thanks everyone!

 

Not sure if you've been in the modern transfer cases, but they are designed to do this and designed well. Doesn't hurt a thing. Yes, it's asking a lot of the synchro, but that's what it's there to do. I shift all the time into 4HI at speed. Zero worries, shifts like a dream.

 

LOL! No kidding. Especially the having to get out and turn/lock the hubs.
I used to carry a can of 'de-icer' or WD-40 in the glove box ... Along with a pair of channel-locks ... Just to make sure I could get the hubs turned/locked sometimes. Hey, that was some old-school manly-man shit back then. Not the sissy-ass 'Push A Button' stuff now days ... LOL!!!

 

Man you got that right. Where I live I always laugh at the ones who it's they're 1st year of driving in snow/ice/NASTY whatever.
They think that because they have AWD, they can drive like it's the middle of summer. Countless times, I've seen them sideways in a ditch.

 

Yes sir .
I have been into thousands of modern transfer cases . Its what I do for a living . I am not basing my opinion on a hand full of trucks .
I am not smarter than the engineers who designed them . They function very well . I only suggested that I personally slow down to make the shift into 4hi . The chain as well as the synchronizer take a beating at those speeds .

 

Old school habits (but I haven't broken anything in all these years either):
I still stop to shift in to 4WD and back up after going back to 2WD
Bonus old school:
My tired old Ranger required a double clutch to shift down to second gear, more often than not I still do it with the Tacoma.

 

Without going out to my cold garage and getting the owners manual, whats the approved way to shift from 4 Hi back to 2 Hi? Stop, slow down and let coast or best way?? Thanks. Yes I came from a push button Silverado.

 

As everyone else said, dont worry about it, but dont do it again. Right after i got mine I was doing curbside pickup (thanks covid) and went to turn the AC up and turned the wrong knob (seriously, why is the 4x4 knob right next to the fan knob?).

The dash light alerted me to my mistake, switched back to 2hi, but it wouldnt disengage while sitting there. Had to back out and turn slightly and got the terrifying pop sound from the binding. Was in a huge panic haha. 3k miles later and no issues

 

Damage from driving in 4X4 on dry pavement is cumulative. Parts rarely break at the time, but they are stressed and over time will wear out prematurely. Of course in extreme situations they can. Almost everyone with a 4X4 has done something similar and if it happens on the rare occasion most of us will never keep one long enough to see the damage. I would certainly not advise making a habit of driving on pavement in 4X4 like some do.

The 10 miles/month advice is good advice. But find a dirt or gravel road to do this. Do not try this on pavement. And 4X4 is not intended for use on wet pavement either.

The inside of the transfer case uses a drive chain similar to a large bicycle chain to transfer power to the front driveshaft. If driven in 4X4 on surfaces with good traction it puts a lot of stress on the chain. Over time the chain stretches and will get loose enough to slip on the gears. This creates a loud popping sound and the truck will hesitate as the chain slips on the gears. Only happens when accelerating from a stop. Once underway it drives normally. But the only fix is an expensive transfer case rebuild.

BTDT twice in my life 40+ years ago as a teenager. I had a 4X4 truck that used vacuum lines to shift from 4X4 to 4X2. At some point before I bought the truck used those lines had gotten reversed. I was in 4X4 when the switch said 4X2. I was smart enough to know better than to be in 4X4 on pavement, but not experienced enough to recognize the problem until it was too late. It was only after the transfer case had to be rebuilt the 2nd time in a few months that the real problem was found. My dad thought I was just trashing the truck.

 

Back in the 80s I plowed for the city as a private contractor just outside of Boston. 1981 Chevy 2500 with manual locking hubs. Was plowing one night, came off a snowy secondary road onto a wet salted road and that was it - front differential ring gear was in pieces! It's funny now, as they saying goes.

 

So what do you guys do when you're in a chain control/4wd area, but the roads are dry with intermittent snow and ice patches? Stay in 4hi?

I never know what to do in that situation, since its mostly dry pavement, but ice and snow are possible at pretty much any moment...