How Can I Tell If Afm Is Active?

[WESB]

I just bought a 2008 4x4 (5.3L) Sierra with 30k on it. I really like the truck. It doesn't even know my boat is back there.

After pulling up the VIN I noticed that it has (at least according to sheet) AFM feature. I'm assuming this is standard on all of these trucks. Is there any indication when it's active? The DIC only has the reset and no buttons, so I don't know if that's where it should indicate. TIA.

[Nick The Great]

My truck has the DIC with the 4 button. In the same display as the Instantaneous Mileage, there is a V8 Mode or a V4 Mode showing.

 

Sounds like you don't have a DIC

 

Lots of people have added this to their trucks. Sounds like it's pretty straightforward, but I've never done it personally. Do a search and theres lots of thread about it. But read about it here to start: http://www.gm-trucks.com/forums/index.php?showtopic=63291

[nickvrebel]

that link is irrelevant, it refers to the GMT 800 trucks, the GMT900 is a different animal

 

it's very simple install http://www.gmpartsdirect.com/results.cfm?s...number=19159438

and you'll have DIC controls.

[Nick The Great]

Thanks NickV. I was trying to post daddy's install thread, but grabbed the wrong one, I guess.

 

http://www.gm-trucks.com/forums/index.php?showtopic=63291

 

That is the thread I was trying to show him.

 

[Silverado4x4]

Thanks NickV. I was trying to post daddy's install thread, but grabbed the wrong one, I guess.

 

http://www.gm-trucks.com/forums/index.php?showtopic=63291

 

That is the thread I was trying to show him.

 

[bb123]

Bottom line is this my friend, ALL 5.3L latest body style have AFM. They all will shift from 8 to 4 cyclinders.

 

Now the 4.8, no.

 

Now, if you get an exhaust you'll be able to tell much easier. Here's what you do.

 

You drive on the hwy on a straight and cruise at like say 70. Don't push the gas hard and slightly let off, just slightly but keep gas on. Now listen to the motor closely. After keeping steady foot now gently hit the gas more and you'll hear the rough sound turn smooth.

 

That is it switching.

 

 

Now, that being said, you need an exhaust to hear it well. I hear mine all day everyday. I adjusted my exhaust and piping today. I took the magnaflow that was connected to the stock pipe that leads to the back of the truck. I then cut the pipe, moved the exhaust closer to the converters, had piping bent and now the exhaust comes out in front of the rear tire. I then put a new different resonator tip on and it completely changed the sound. It sounds good I might add. But back to the story I can go on the hwy and when in 4cyl mode it sounds like a diesel, literally. But once I hit the gas it'll sound like a normal V8.

 

 

Try it out and you'll see....

[TRCM]

Bottom line is this my friend, ALL 5.3L latest body style have AFM. They all will shift from 8 to 4 cyclinders.

 

Now the 4.8, no.

 

Now, if you get an exhaust you'll be able to tell much easier. Here's what you do.

 

You drive on the hwy on a straight and cruise at like say 70. Don't push the gas hard and slightly let off, just slightly but keep gas on. Now listen to the motor closely. After keeping steady foot now gently hit the gas more and you'll hear the rough sound turn smooth.

 

That is it switching.

 

 

Now, that being said, you need an exhaust to hear it well. I hear mine all day everyday. I adjusted my exhaust and piping today. I took the magnaflow that was connected to the stock pipe that leads to the back of the truck. I then cut the pipe, moved the exhaust closer to the converters, had piping bent and now the exhaust comes out in front of the rear tire. I then put a new different resonator tip on and it completely changed the sound. It sounds good I might add. But back to the story I can go on the hwy and when in 4cyl mode it sounds like a diesel, literally. But once I hit the gas it'll sound like a normal V8.

 

 

Try it out and you'll see....

 

 

I have a stock exhaust, as far as I know (bought it used), but I too can tell when it shifts by the sound, even with the windows up.