Driving in 4wd

sdeeter19555 · January 1, 2017

The spiders are still turning, understanding how a front diff works matters in this discussion.

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Silveradotim · January 1, 2017

I have a friend that recently purchased a 2017 GMC Z71 and he wanted to test the 4wd so he put in high and drove about a mile on dry pavement when he smelled something burning.The truck was taken back to the dealer and the service manager told him by doing that on dry pavement he ruined the front transfer case, they installed new bearings etc under the warranty.I have a 2016 Z71 which i tested the 4wd yesterday and it is louder than the Yukon i previously drove but I feel that their was something wrong with his truck from the factory rather than driving in 4wd on dry pavement.

any thoughts

Mark, my truck has a loud front ring and pinion ring at 45 mph and up. It's not the normal 4wd noises, my work truck is a 2015 and it's pretty quiet compared to my 2014.

I am taking it to the dealer next week to get the front diff checked out. Seems like it must have been a Friday that my diffs were built, the rear has been rebuilt with bearings and r&p due to excessive bearing noise. I'm at 90,000miles now so I gotta get it handled soon

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truckguy82 · January 2, 2017

The spiders are still turning, understanding how a front diff works matters in this discussion.

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Without knowing exactly how the entire thing is engaged

I wasn't referring to the front diff. There are mechanical parts that get engaged in 4wd, whether it's an actuator, gears, or clutches. It's probably a good idea to not let these sit without being used for long term.

Just like my dad lost 4lo in his tundra from not engaging for 80k miles. He didn't damage anything, it's just whatever actuates the lo speed gears in the tranfer case is now stuck. He had an expensive quote to "unstick" it

DeltaTek · January 2, 2017

Anybody who's serviced, rebuilt, or built them from new will say it all depends on what type of power train is set up on your truck, these pick ups are designed to go on the highway so you can drive in 4X4 and the auto 4X4 will engage anytime the truck detects slip, but if you engage 4X4 on the highway you shouldn't drive faster than 50mph. That's just the golden rule because if you need to drive in bad weather slippery conditions and need 4X4 maybe anything faster than 50 is probably not a good idea.

deweyg63 · January 2, 2017

Why would it engage at 70? If you're driving 70 on ice you need to rethink your life. Turning tight in 4wd won't hurt anything. The front diff is an open diff.

About this.... I live in Illinois where we sometimes get a lot of ice and snow. Way too many times I have seen a group of as many as 10 cars in the ditch because they were hauling ass on what they assumed were good roads in questionable conditions. Next thing you know cars are flying off the road until the sight of them in the ditch slows the next cars down. I stopped once and drove a young guys car back on the road. He was from Texas and didn't even try to drive out. He was just waiting on the tow truck making his way down the line. After I left I realized I put my life in danger in the icy vehicle pinball game on foot and won't do that again unless I think someone's life is in jeopardy. Bottom line, if conditions are questionable please don't drive 70. I'm not the safety police and don't ever like telling people how to live but give it some thought. Also know that I'm 53. Time, accidents and a much too crazy life experience has taught me well

sdeeter19555 · January 2, 2017

I've been running highway speeds and grabbed 4wd before...when it goes bad, sometimes that is the difference between continuing down the road or being part of that pile up...did I continue to drive down the road that way, no. But sometimes conditions go from good to worse than bad in a matter of 100 feet of highway. I've got over a million miles of seat time between just three personal pickup trucks, seen a lot.

And yeah, Illinois is one of those states it can go from dry highways to ice and snow covered in a 100 feet...been there, done that, saw almost 100 cars in the median on that trip alone.

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sdeeter19555 · January 2, 2017

Without knowing exactly how the entire thing is engaged

I wasn't referring to the front diff. There are mechanical parts that get engaged in 4wd, whether it's an actuator, gears, or clutches. It's probably a good idea to not let these sit without being used for long term.

Just like my dad lost 4lo in his tundra from not engaging for 80k miles. He didn't damage anything, it's just whatever actuates the lo speed gears in the tranfer case is now stuck. He had an expensive quote to "unstick" it

That failure was likely nothing more than coincidence...and would have likely failed regardless of use.

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truckguy82 · January 2, 2017

That failure was likely nothing more than coincidence...and would have likely failed regardless of use.

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Actually the toyota dealer said it was common with people that don't engage 4lo for long period of time.

It's not like its a complicated matter. Like any lubricated moving part in any machine, if something stays stationary for years it's probably going to stick a little when you first try to move it. If the machines electronic means of moving it is not powerful enough to unstick it, then it will not work.

You can't tell me there are no parts that only move when you engage 4wd. I know we have electric actuators atleast. So I'm sticking with my logic until proven otherwise because you only need to flip a switch and it does no harm.

Archaic2021 · January 2, 2017

Does the owner manual say not go over 55mph?

Just wondering I know over on some of the performance websites guys use 4WD to launch at the drag strip.

Jon A · January 2, 2017

Wimps. Auto mode works beautifully at 80+ MPH .

Seriously, if you're driving 50 MPH on a freeway in the west and it's anything less than an all out blizzard so heavy you can't see the front of your hood or completely shiny glare ice you are going to get run over--and you're actually endangering others as people will get so pissed off when stuck behind you they'll pass you in a dangerous manor. There are an infinite number of conditions short of those extremes in which a little added traction may be desired.

The system is intended to work at actual highway speeds. If it does not, the solution is to get it fixed...not tell the guy to abstain from using it.

sdeeter19555 · January 2, 2017

Actually the toyota dealer said it was common with people that don't engage 4lo for long period of time.

It's not like its a complicated matter. Like any lubricated moving part in any machine, if something stays stationary for years it's probably going to stick a little when you first try to move it. If the machines electronic means of moving it is not powerful enough to unstick it, then it will not work.

You can't tell me there are no parts that only move when you engage 4wd. I know we have electric actuators atleast. So I'm sticking with my logic until proven otherwise because you only need to flip a switch and it does no harm.

Then that is an engineering/design failure...

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sdeeter19555 · January 2, 2017

Does the owner manual say not go over 55mph?

Just wondering I know over on some of the performance websites guys use 4WD to launch at the drag strip.

A lot of the diesel guys have to launch in 4wd...there is no limit to the speed, but road conditions might dictate otherwise...

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Z45 · January 2, 2017

AUTOMATIC TRANSFER CASES
These transfer cases have a 2HI, Auto-4WD, 4HI, 4LO and Neutral position and would fall in the general 4WD category. This transfer case has the operating characteristics of both an On Demand AWD and a Part-Time 4WD system depending on the mode selected. This transfer case uses a clutch pack to allow for a difference in speed between the front and rear axles in the Auto-4WD mode. In the 4HI or 4LO modes, there is no allowance for the difference in speed between the front and rear axles.

Driving in AUTO is no different than driving an ALL WHEEL DRIVE.

Z45 · January 3, 2017

Just wondering I know over on some of the performance websites guys use 4WD to launch at the drag strip.

When racing the object is to win at all costs and not worry about breaking something.......

truckguy82 · January 3, 2017

When racing the object is to win at all costs and not worry about breaking something.......

Guys run 10's in 4wd with these trucks

I actually think launching in 4wd is a little safer than 2wd

In 2wd, you send 100% of your power to 1 driveshaft and 1 diff, in 4wd, you take some of the load off the components in the rear.

The 4wd system in these trucks is absolutely badass

We have selectable 2wd, awd, 4wd, and 4wd lo, which is awesome.....and If that wasn't enough, it's also stout enough to handle a ton of power in stock form.