New truck, 2014 Silverado Z71, help put my mind at ease?

[MJFlores]

Hi all, I'm starting to worry about my new truck (yes, I'm a worrier!). I have just over 500 miles on it, Since I got it I was having a weird drone sound in the front end on acceleration and was just observing things over the past week. This am on the way to work I came down an off ramp and smelled a faint "burning oil smell". I figured ok, to the dealer we're going to get it looked at. They couldn'nt find any oil leaking and the guy noticed I had the heater on and it was set to draw air from outside rather than recirculate and said with the new motor breaking in that may have been the smell I got. Sounds reasonable. He then noticed I had the 4 wheel drive switch set to "auto" instead of "2 wheel". Really nice guy, he went on to let me know that you can burn up the front diff (I think he said) by driving around with that setting all the time. Then it clicked..Ah that must have been the noise I heard. I drove off with air recirculating and the 4 wheel setting on 2 and everything is great now. It all seems simple huh?...yeah, I feel like a dummy for not trying that switch. My last truck was a 2010 Silverado and I left it on "auto" all the time, even in the summer and never heard a noise. Anyway, now I'm worrying ...was the oil burn smell coming from the front diff and could I have cooked the fluid? It was actually snowy this am (we got 12 inches of snow yesterday) so I would think it was the perfect scenario to have the switch set to "auto" but who knows. My girlfriend tells me I need to quit worrying and just drive it LOL. I wonder if I should bring it in for a front diff fluid change or do you think I'm good? I mean, when I got to the dealership the truck only had 480 miles on it. I have a long dirt driveway covered in snow right now so when I pulled in I stopped and put it in 4 wheel high and drove for a few hundred yards and everything sounded and felt ok, front was engaged, etc. Anyway, just looking for advice ...change the fluid in the front diff or stop worrying and try to enjoy the new truck?

[VMaxtastic]

Even on dry pavement, running it in 4 Auto isnt too terrible, 4Hi is a different story..... I dont use it unless I have to, but I doubt it caused an damage, especially if it was icy and there was snow on the road For the first little bit mine had a burning plastic kinda smell, but it has gone away now. I just assumed it was a fresh motor breaking in, like the guy sad.

[6Sixathome]

Your truck is fine, you don't need to change the front diff fluid for that little bit it auto. Don't worry anymore, just drive and enjoy it.

[Silverado Steve]

Stop worrying. The oil smell is the wax coating burning off the underside of your truck, plus the new engine. In 4wd auto, the hubs engage, but power not sent to the front diff unless slippage is detected at the back wheels. Bottom line, you're fine...quit worrying and sleep well at night. Enjoy your truck.

[Imcrazy]

Like others said you should be just fine!

[cansled]

I have had mine in 4wd AUTO for most of the winter. I thought it is perfectly fine to run it in that mode regardless of the road surface. Maybe a little less MPG, but how can it hurt the drivetrain? 4WD HI is a different story.

[cansled]

I have had mine in 4wd AUTO for most of the winter. I thought it is perfectly fine to run it in that mode regardless of the road surface. Maybe a little less MPG, but how can it hurt the drivetrain? 4WD HI is a different story.

[mattmanstroked]

I wouldn't worry about it like other's have said.

 

You can do a test in auto by turning sharp ok now do the same turn in 4 high you can feel the binding in the front end while turning.

 

It is kind of a let down on GM's part not to have a better four wheel drive indicator in the cluster besides the little bitty light by the four wheel drive switch. Could have done better on that.

[fondupot]

But for the record. Running around in auto is a waste of gas and does add un-needed wear to the 4 wheel drivetrain because instead of acting like a passthrough, the transfer case is engaged.

 

When rolling around on dry pavement keep it in 2 hi.

light snow and rain - use auto

heavy snow and offroad - use 4 hi

slower speeds offroad use 4lo

[MJFlores]

Thank you ever body! I feel better after reading your replies and advice. I do appreciate it!!

[2017HD]

I always thought that the front diff and driveline were turning all the time and the only difference in the drive modes were if the transfer case was actually applying power to them. In 4hi/lo the transfer case is engaged all the time, in Auto it engages only when rear wheel slippage is sensed and in 2Hi it is disengaged. So you could run in auto all the time and not have any problems with the front end.

[Silverado Steve]

^ this

[MikeNH]

I don't think the front components are constantly engaged, the t-case has a shift fork or in this case a clutch and the front axle usually has some sort of disconnect. That said, there is no good reason to run in auto year round, it will burn up fuel and cause unneeded wear on the driveline.

[Silverado Steve]

^ this the only thing is the front hubs stay locked

[tbarn]

The front axle is engaged in all except 2 wheel high range. The transfer case applies torque the the front axle only as required (slippage of rear wheels).

"AUTO (Automatic Four-Wheel Drive)

Use when road surface traction conditions are variable. When driving in AUTO, the front axle is engaged, and the vehicle's power is sent to the front and rear wheels automatically based on driving conditions. This setting provides slightly lower fuel economy than 2 hi.

Do not use AUTO mode to park on a steep grade with poor traction such as ice, snow, mud, or gravel. In AUTO mode only the rear wheels will hold the vehicle from sliding when parked. If parking on a steep grade, use 4 hi to keep all four wheels engaged."