AFM Newb question

[Mickey_7106]

How do i know if my truck is equipped with it?

 

[iamdub]

Other than feeling it engage V4 Mode (not everyone can tell), the easiest way is to, while idling, press the DIC control button (top one?) to cycle through the screens until you see one that displays your instant fuel economy. To the right it will say "V8 MODE". Leave it there and drive easily. At a steady speed above ~30MPH, if it displays "V4 MODE", then you have AFM.

DIC control buttons:

V8 MODE:

V4 MODE:

 

[Chrismnj]

From what I understand, all 2007.5 on up trucks with the 5.3L are AFM.

 

[swathdiver]

How do i know if my truck is equipped with it?

What are you driving?

 

[Mickey_7106]

Thanks. I've gone through the DIC menu to "instant economy" while driving at 70mph to see how much i was getting on E85 (11 mpg on mostly flat road) but i didn't notice the "v8 or v4". I drive a '09 yukon xl 4x4

 

[swathdiver]

I drive a '09 yukon xl 4x4

So do I. You should be getting 14 or more at 70 on E85. Lots of things come into play though.

 

[Mickey_7106]

I feel the same way, but i don't drive it enough for it to bother me. I was getting about 15-20mpg on my '06 Silverado CC with all terrain tires and 4 speed trans

So do I. You should be getting 14 or more at 70 on E85. Lots of things come into play though.

 

[swathdiver]

I feel the same way, but i don't drive it enough for it to bother me. I was getting about 15-20mpg on my '06 Silverado CC with all terrain tires and 4 speed trans

Well, it may be a sign of something amiss. I ran 7-11 miles each way for a 2-way average and did it 3-6 times for every 5 mph from 35 to 80. Did not use the instant though, I reset the regular counter for each leg of each run. Did it for gasoline, E85 @ 72%, E85 @ 80% and may soon do it for E30 @ 25%. Also running an AT tire.

 

[Mickey_7106]

I just remembered that i was driving in 4Hi most of my trip due to terrible weather so the 11 mpg is probably the norm

 

[swathdiver]

I just remembered that i was driving in 4Hi most of my trip due to terrible weather so the 11 mpg is probably the norm

Yeah, that'll do it (bad weather and 4x4)! Do you not like 4Auto? I've done both in terrible weather but not sure why I would or should prefer one mode over the other while cruising down the highway.

 

[PG01]

Yeah, that'll do it (bad weather and 4x4)! Do you not like 4Auto? I've done both in terrible weather but not sure why I would or should prefer one mode over the other while cruising down the highway.

Ill use auto instead of 4 hi most of the time, even plowing.

 

[Mickey_7106]

I don't know how 4 auto works. I do set it there when we get lite rains. It's kind of peace of mind for me. I throw it in 4 hi when the weather is shit along with the roads. Not sure how quick 4 auto will activate when I'm going +65mph and every second counts to react .

 

[Mickey_7106]

Btw, how do you know what the content of your e85 is?

Did it for gasoline, E85 @ 72%, E85 @ 80% and may soon do it for E30 @ 25%. Also running an AT tire.

 

[swathdiver]

Btw, how do you know what the content of your e85 is?

I use a scan tool (Tech-2) to see it.

In 4Auto, the front driveshaft is spinning but no power is sent to the axle unless the computer says so. With KO2s and on the street, it's overkill, but like you said, peace of mind for when my wife and children are driving it too.

 

[intheburbs]

I don't know how 4 auto works. I do set it there when we get lite rains. It's kind of peace of mind for me. I throw it in 4 hi when the weather is shit along with the roads. Not sure how quick 4 auto will activate when I'm going +65mph and every second counts to react .

4Hi - four-wheel drive engaged, engine power going to all 4 wheels
4Auto - front hubs locked, transfer case in "standby mode," and engages whenever slip/skid is detected. It's pretty fast to engage - less than a second.

You should only be using 4Hi when you're driving on low-traction surfaces - snow, slush, dirt, etc. There is no center differential, so any turns will cause the tires to scrub and bind the driveline.

You also shouldn't drive over 60 mph in 4 Hi (and no faster than 45 in 4Lo).

 

[Mickey_7106]

Welp, i guess i missed the "v8,v4" the first time on the DIC. I noticed it this am.

4Hi - four-wheel drive engaged, engine power going to all 4 wheels
4Auto - front hubs locked, transfer case in "standby mode," and engages whenever slip/skid is detected. It's pretty fast to engage - less than a second.

You should only be using 4Hi when you're driving on low-traction surfaces - snow, slush, dirt, etc. There is no center differential, so any turns will cause the tires to scrub and bind the driveline.

You also shouldn't drive over 60 mph in 4 Hi (and no faster than 45 in 4Lo).

Thanks for the breakdown. This is the first time I've read a limitation for 4hi. I just assumed it would drive the same as an awd

 

[thompsoj22]

Welp, i guess i missed the "v8,v4" the first time on the DIC. I noticed it this am.




Thanks for the breakdown. This is the first time I've read a limitation for 4hi. I just assumed it would drive the same as an awd

Will an AWD perform just as well as the 4WD on snow and ice?

 

[swathdiver]

Will an AWD perform just as well as the 4WD on snow and ice?

For the most part, yes. A 4x4 gives you more options though.

 

[thompsoj22]

For the most part, yes. A 4x4 gives you more options though.

Thanks, just finished a trip to mammoth. bought chains for the denali, read the owners manual "do not install chains" returned chains and bought a set of cables for the toyota corolla and took that little cracker box instead. While in mammoth im watching all the XL1500 awd driving everywhere with no problem and no chains! It was full on blizzard conditions roads were 100% packed/drifting snow, oh well live and learn. Next time ill take the denali.

 

[Mickey_7106]

Thanks, just finished a trip to mammoth. bought chains for the denali, read the owners manual "do not install chains" returned chains and bought a set of cables for the toyota corolla and took that little cracker box instead. While in mammoth im watching all the XL1500 awd driving everywhere with no problem and no chains! It was full on blizzard conditions roads were 100% packed/drifting snow, oh well live and learn. Next time ill take the denali.

Yeah, you can get by if you go at a slow pace. I drove through a similar situation from Arnold, ca to bear valley in my silverado 4x4.