GMC All Terrain 5.3 - a couple of questions about breaking it in

bladz1454 · November 11, 2013

Hi All,

This is my first post so I am sorry if these questions are "stupid". So I finally went back to owning a truck (had a F150 for years and traded it for a commuter car and couldn't deal without the size anymore so I decided to finally get a GMC!), just hit 500 miles on my 2014 All Terrain with 5.3 motor Crew Cab 4x4 and wanted to see if any one can shed some light on some concerns I had so far.

1 - I have been doing about 50/50 city and highway driving and I will say I drive like a slow poke grandpa, always easy off the line and average about 65 mph on the highway. So I have been getting around 15 mpg... is this normal? I did read a few topics of people average 20 mpg who drive harsher than me but also have a couple thousand miles on their motors so is this a "as the motor breaks in the mileage gets better" issue?

2 - So as I said, I just hit 500 miles and I know the dealership told me I get free oil changes every time the computer says its time but shouldn't I be changing my oil the first 500-1000 miles to get out all the break-in shavings? Or is this just something we used to do with older vehicles?

3 - My last truck with only 2 wheel drive and this Sierra has a the 2 rear and 4 auto settings (the other 4 wheel options as well) and wants to know, should I keep it in 2 wheel rear or 4 auto? Someone was explaining to me that they are the same exact thing except when the front wheels need traction they will engage when needed?

Thanks a lot guys! I'm stoked to finally join the GMC family and so far I have gotten nothing but head turns and compliments on the 2014 Sierra so I'm hoping the truck does end up getting better MPG.

-Drew

kstruckcountry · November 11, 2013

Welcome.

I can't speak for anything else, but Auto 4x4 is best for icy or snowy conditions when you don't constantly need 4x4. There's really no reason to use it on dry pavement, 2 wheel drive is best for that.

primomarcelino · November 11, 2013

I have the same truck and do 50 city 50 hiway. I now have 1200 kms. So far I am getting 600km for 90 litres. Or 15 litres per 100 km or 18mpg. This is with me driving it gingerly. So far the mileage is acceptable and if it improves after a break in period, I would be impressed.

jay15892 · November 11, 2013

Welcome.

I can't speak for anything else, but Auto 4x4 is best for icy or snowy conditions when you don't constantly need 4x4. There's really no reason to use it on dry pavement, 2 wheel drive is best for that.

Ditto. 4 auto is nice because you don't need it locked in four wheel drive. It does engage the front axle though and modulates it at the transfer case. So 4 auto is pointless if it is dry out.. Also on mine after 1000 or so miles the truck seemed to loosen up a little and drives real nice now.

redwngr · November 11, 2013

Hi All,

This is my first post so I am sorry if these questions are "stupid". So I finally went back to owning a truck (had a F150 for years and traded it for a commuter car and couldn't deal without the size anymore so I decided to finally get a GMC!), just hit 500 miles on my 2014 All Terrain with 5.3 motor Crew Cab 4x4 and wanted to see if any one can shed some light on some concerns I had so far.

1 - I have been doing about 50/50 city and highway driving and I will say I drive like a slow poke grandpa, always easy off the line and average about 65 mph on the highway. So I have been getting around 15 mpg... is this normal? I did read a few topics of people average 20 mpg who drive harsher than me but also have a couple thousand miles on their motors so is this a "as the motor breaks in the mileage gets better" issue?

2 - So as I said, I just hit 500 miles and I know the dealership told me I get free oil changes every time the computer says its time but shouldn't I be changing my oil the first 500-1000 miles to get out all the break-in shavings? Or is this just something we used to do with older vehicles?

3 - My last truck with only 2 wheel drive and this Sierra has a the 2 rear and 4 auto settings (the other 4 wheel options as well) and wants to know, should I keep it in 2 wheel rear or 4 auto? Someone was explaining to me that they are the same exact thing except when the front wheels need traction they will engage when needed?

Thanks a lot guys! I'm stoked to finally join the GMC family and so far I have gotten nothing but head turns and compliments on the 2014 Sierra so I'm hoping the truck does end up getting better MPG.

-Drew

#2 Yes that's just something we used to do.

#3 Put it in 2wd.

fondupot · November 11, 2013

1. Yes your mileage should get better. I do mostly around town driving and my first few tanks have been 15.7 mpg, the next 16.4, and the current tank ive been getting 17.5 (according to DIC). Also, depending where you live gas stations have switched to winter blend gas, which will lower mpgs as well. I have about 1400 miles on mine now. And it definitely feels like it has woken up since the day I bought it. I love it so far.

2. I brought this issue up with my dealer, they said that the dealer will only change the oil when the DIC oil change percentage is below 10% (I think thats what they said). Ive done some rough calculations and at the current rate of the % going down and my mileage, I should be at 10% between 6800-7200 miles. I too have felt the need to change the oil sooner. But the dealer has assured me multiple times (as if it means anything). That there is no need. These motors might be broken in from the factory so the shavings you are talking about might be a thing of the past.

3. 2 HI - Normal dry pavement conditions. (transfer case is not engaged)

Auto - Wet pavement from rain and light snow, (transfer case is engaged, but the computer senses slippage and the front diff will apply power to the front wheels when it detects rear wheel slippage.)

4 HI - Wet pavement from heavy snow, and offroad. No higher than speeds up to 35/40 mph (transfer case engaged, and differential locked in to power all four wheels)

4 LO - not for use on pavement. Primarily for offroad, LOW speeds. (transfer case engaged and differential locked in to power all four wheels.)

Enjoy the truck!

bladz1454 · November 11, 2013

1. Yes your mileage should get better. I do mostly around town driving and my first few tanks have been 15.7 mpg, the next 16.4, and the current tank ive been getting 17.5 (according to DIC). Also, depending where you live gas stations have switched to winter blend gas, which will lower mpgs as well.

2. I brought this issue up with my dealer, they said that the dealer will only change the oil when the DIC oil change percentage is below 10% (I think thats what they said). Ive done some rough calculations and at the current rate of the % going down and my mileage, I should be at 10% between 6800-7200 miles. I too have felt the need to change the oil sooner. But the dealer has assured me multiple times (as if it means anything). That there is no need. These motors might be broken in from the factory so the shavings you are talking about might be a thing of the past.

3. 2 HI - Normal dry pavement conditions. (transfer case is not engaged)

Auto - Wet pavement from rain and light snow, (transfer case is engaged, but the computer senses slippage and the front diff will apply power to the front wheels when it detects rear wheel slippage.)

4 HI - Wet pavement from heavy snow, and offroad. No higher than speeds up to 35/40 mph (transfer case engaged, and differential locked in to power all four wheels)

4 LO - not for use on pavement. Primarily for offroad, LOW speeds. (transfer case engaged and differential locked in to power all four wheels.)

Enjoy the truck!

Man that was quick, thanks for all the answers guys - this is all good to know. That is also good to know Fondupot, about the MPG hopefully and the oil change. I totally forgot about the winter blends too, I live in Connecticut and I think they switched over at the end of October so that would explain a little bit of the MPG as well.

Thanks everyone!

GMCustomerService · November 11, 2013

bladz1454,

Hello and congratulations on the new vehicle. I see that the awesome forum members answered all your questions. I just wanted to stop by and let you know that GM Customer Care is here as well on the forum and happy to assist with any general questions or concerns you may have about GM products. We are only a private message away!

Safe Travels,

Jennifer T.

GM Customer Care

fondupot · November 11, 2013

Man that was quick, thanks for all the answers guys - this is all good to know. That is also good to know Fondupot, about the MPG hopefully and the oil change. I totally forgot about the winter blends too, I live in Connecticut and I think they switched over at the end of October so that would explain a little bit of the MPG as well.

Thanks everyone!

Also, driving technique is a big player in MPG. Not saying you're an erratic driver, but think about your driving habits. A lot of stops and go's? Hard stops? excessive idling? hills? hard acceleration? etc.

also, if your tires are set at the the sticker on the door sill, go ahead and bump them up a few PSI. The truck might ride a bit worse, but it should help mpgs as well. I run my tires at 38-39 psi cold (i have the 20" wheels and tires).