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I misinterpreted the way this feature works. I thought it was more of an AWD feature. No. I just read a better written description from GMC and they're calling it Auto 4 Hi. They say it's fine for any driving condition but will cause wear faster to 4x4 driveline. I have 35k and I'd say possibly half that was on Auto 4x4. Either on the highway or riding through potholes at average 30 MPH. What can I say for what I've done to the truck? About to do the first transmission and differential service. I use the severe chart as I'm in New York City and Long Isiand.
 

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This is why reading manuals with vehicles is important. Hopefully you make it out unscathed. That's definitely not good though. Switch your fluids for sure. I'd be sure to inspect the fluids you pull out. T-case fluid, rear end fluid especially should be checked for any metal shavings.
 

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It says when traction conditions vary. That is vague. My traction varies when dropping int 6 inch deep potholes. Or just out of nowhere a roads are so uneven it's like riding down a trail. Now I know that's not slippage like dirt but it doesn't say that. I know this is my fault but the new description and calling it AUTO 4 Hi would have been nice.

http://m.gmc.com/gmc-life/how-to/when-t ... drive.html

Copy and pasted from my manual:
AUTO (Automatic Four-Wheel Drive): This setting is ideal for use when road surface traction conditions are variable.
 

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Being I grew up with 4x4 trucks. Honestly never thought this was an issue until recently. Had a friend who came from Subaru cars who ran his truck in 4 wheel because he did not understand the difference. Bound up t-case and a snapped axle later he learned his lesson. Seems like this is something more people need a much better understanding of. 4x4 is meant for when the tires are slipping and sliding not just a bounce or uneven road surface. Heck, 90% of the time you don't even need it on dirt roads and often not even in light snow. AWD and 4 wheel drive are very different in both function and purpose. Variable road conditions means snow, slush, ice and sometimes flooding. In reality though. If you don't take the truck off road and know how to drive in bad weather conditions. You may never need to put it in anything other than 2 wheel. Basically, unless you are actually experiencing control issues or getting stuck. 4wd is not what you need. The entire purpose of the Auto 4 wheel is that when the truck does have a tire break free it engages to keep the truck going straight. Going around sharp turns can and will engage 4 wheel drive as the outside tires will be traveling at a higher enough rate of speed than the inside to make the truck think that a tire is slipping. That is where binding will occur.
 

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Driving 35,000 miles in Auto is not optimal but it isn't any where near as bad as driving if 4HI. My dealer said he puts his wife's truck in 4Auto at the start of winter and leaves it that way until the snow ends in the spring. Would I do that? Hell no. But I would drive 100 miles with it in 4auto if I was on roads that had intermittent snow and ice. The truck is designed to drive in 4auto for extended periods of time, just not all the time. Parts of the 4wd system are always locked in under 4auto and will constantly be turning, just not engaged on dry ground. That is where the extra wear and tear come in. It isn't like the system is locked in and binding all the time.

Regarding the OP, I would replace the transfer case fluid immediately and start using the 4wd system the correct way going forward.
 

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A coworker of mine has a 08 silverado extendend cab 5.3 4 spd , and has kept it in auto 4 wheel all summer and winter for probaly 130,000 miles. Only to switch to 4 wheel drive sometimes in the winter and has never had a problem as of yet. I have said stuff to him in the past about that , but he does not care, does not want to slip and slide in the rain or on a gravel road he said . And he does not do regular maint. of anything besides oil changes also. I would not let it keep you up a night . Change your fluids and go on your way...
 

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When your co-workers 4WD light comes on, point him to silveradosierra.com so we can make fun of him. Seriously though, running your truck in 4auto all summer long is just plain dumb. But whatever. He may get another 130,000 miles out of it, but more likely, he will be replacing 4WD components. Also, 4auto will cut into fuel mileage since it has the extra components engaged at all times.
 

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I suppose he is one of those types who won't change their motor oil until they hear a noise.
 

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I'm not sure they should have even made auto an option. It could get some people in trouble while driving instead of out of trouble if activated at the wrong time.
 

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On a trip from Atlanta Ga to Philadelphia Pa I took headed into a bad sleet storm the end of February 2015 I can say 100% that the auto 4 wheel works and is a great feature to have. I hit the beginning of the mess in southern Virginia and was able to continue without any trouble besides a slowed pace. Every time the truck would slide it kicked in and straightened me back out perfectly. You can't not make advancements because some people won't learn how to use it first.
 

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Fisger8new said:
On a trip from Atlanta Ga to Philadelphia Pa I took headed into a bad sleet storm the end of February 2015 I can say 100% that the auto 4 wheel works and is a great feature to have. I hit the beginning of the mess in southern Virginia and was able to continue without any trouble besides a slowed pace. Every time the truck would slide it kicked in and straightened me back out perfectly. You can't not make advancements because some people won't learn how to use it first.
That might have been more a result of stabilitrac and traction control than the 4auto....that is provided your truck has those two features.
 

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My father's old 2009 has 120k when he traded it in. The majority of that was in auto mode. It still worked fine and didn't have any issues. I wouldn't do it on my vehicle though. My 01 is either in 2wd or 4wd. I don't see the point in auto really.

However, when there are perhaps less experienced drivers or something like that, I think auto could be a good use there since it might save them a time or two.

Sent from my SM-N910V using Tapatalk
 

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esox07 said:
Fisger8new said:
On a trip from Atlanta Ga to Philadelphia Pa I took headed into a bad sleet storm the end of February 2015 I can say 100% that the auto 4 wheel works and is a great feature to have. I hit the beginning of the mess in southern Virginia and was able to continue without any trouble besides a slowed pace. Every time the truck would slide it kicked in and straightened me back out perfectly. You can't not make advancements because some people won't learn how to use it first.
That might have been more a result of stabilitrac and traction control than the 4auto....that is provided your truck has those two features.
My truck does not have stabilitrac or traction control. That was purely the 4w auto and simply knowing how to drive in the conditions. Steady throttle and braking with no sudden turning of the wheels.
 

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You don't have AWD on your truck. You have 4WD. There is a difference.
 

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Auto 4WD, or AWD - I know they are not the same, but I agree that it is the best $300 and something dollars I spent on my truck.

Looks like the cold weather has set in here, so it will probably stay in Auto until spring. I like to know that the truck will move when I step on the gas and with the constant combination of wet, snow and ice we have here for most of the winter the Auto setting works best.
 
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