Long term driving in manual 5th??

Dexter10 · March 24, 2017

Donstar-I didn't mind it really with my stock exhaust. With my new exhaust when going into V4 it sounds aweful so I want to avoid that.

I knew this before the purchase of the MBRP so at the moment this is my cure to that farting sound when in V4.

gmissed · March 24, 2017

I read what others have said but I am curious as to why you don't like your truck in V4 mode? You should only notice the change by the indicator in your DIC. Your truck has an abundant amount of power and it makes sense to reduce use when the need isn't there. I believe there is some stigma associated with running in V4 when we paid for a V8. I still feel the same way about driving a truck with an automatic transmission! If you're noticing any lack of responsiveness or power as a result of the technological advancement of AFM then your vehicle needs service, imo.

I'm with you on this one. I've often wondered why some don't like it as well. I never notice when it goes in/out of V4/V8 and if it saves some gas then all the better.

Cowpie · March 24, 2017

A casual read thru various threads on all the GM related pickup forums should satiate your curiosity on why many folks despise the AFM thing. My basic understanding of hrydraulic lifters and how AFM does its thing and how the motor oil that is used in that function is affected was enough to convince me that I didn't care for AFM. I didn't do my homework as I should have before buying the 1500 or I wouldn't have. But it is a non issue now that I went back to a 2500.

Edited March 24, 2017 by Cowpie

Sierra706 · March 24, 2017

I read what others have said but I am curious as to why you don't like your truck in V4 mode? You should only notice the change by the indicator in your DIC. Your truck has an abundant amount of power and it makes sense to reduce use when the need isn't there. I believe there is some stigma associated with running in V4 when we paid for a V8. I still feel the same way about driving a truck with an automatic transmission! If you're noticing any lack of responsiveness or power as a result of the technological advancement of AFM then your vehicle needs service, imo.

Some are more sensitive to their vehicles than others. Driving styles also vary. Does your 6 cylinder have afm?

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KARNUT · March 24, 2017

More stuff in the motor to break, 300K miles on a 5.3 without internal work not likely.

Donstar · March 24, 2017

Some are more sensitive to their vehicles than others. Driving styles also vary. Does your 6 cylinder have afm?

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Yes the 4.3 has AFM. I can often predict when I may expect to see V4 light up but I can honestly say there is no feel or sound that indicates the change. My 09 Sierra had the 5.3 with AFM and it wasn't noticeable but I also didn't pay attention to it until reading concerns about AFM on this forum!

Sierra706 · March 25, 2017

Yes the 4.3 has AFM. I can often predict when I may expect to see V4 light up but I can honestly say there is no feel or sound that indicates the change. My 09 Sierra had the 5.3 with AFM and it wasn't noticeable but I also didn't pay attention to it until reading concerns about AFM on this forum!

I can hear the difference, and feel a noticeable shudder when it switches back to 8 cylinder. Quite possibly the V6 has a smoother operation than the 8 cylinder.

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gmissed · March 25, 2017

I can hear the difference, and feel a noticeable shudder when it switches back to 8 cylinder. Quite possibly the V6 has a smoother operation than the 8 cylinder.

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I have the 6.2 and honestly cannot tell when it moves in/out unless I happen to be looking at the dic.

dasimmon · March 25, 2017

A casual read thru various threads on all the GM related pickup forums should satiate your curiosity on why many folks despise the AFM thing. My basic understanding of hrydraulic lifters and how AFM does its thing and how the motor oil that is used in that function is affected was enough to convince me that I didn't care for AFM. I didn't do my homework as I should have before buying the 1500 or I wouldn't have. But it is a non issue now that I went back to a 2500.

need to bite the bullet and make the change to diesel

Sierra706 · March 26, 2017

I have the 6.2 and honestly cannot tell when it moves in/out unless I happen to be looking at the dic.

Before my Corsa it was harder for me to tell, but I could still feel it slightly and the flapper valve would chirp. Now with the exhaust it is noticeable both with the change in exhaust tone and along the power train.

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Cowpie · March 26, 2017

need to bite the bullet and make the change to diesel

I already own enough diesels. I go thru around 20,000 gallons of diesel a year. I don't want the Dmax in my pickup. I never have had a fondness for V engines anyway, and I will not buy a V diesel, I don't care who makes it. My 2500 only racks up enough miles in a year to justify one oil change per year, and my oil change regimen is every 6000 miles or one year. A diesel under those circumstances would be stupid. My 2500 goes for weeks between startups sometimes.

Edited March 26, 2017 by Cowpie

Cujoxx67 · August 16, 2022

On 3/23/2017 at 4:03 PM, Dexter10 said:

Hey all. I am new to the forum with a 2015 Sierra 1/2 ton. I installed a cat back MBRP system and love it. Except when in V4 mode. I knew this before the install and plan on picking up a Range AFM if I can find a cheaper used one. Until then I am driving in M5 mode unless above 60mph.

Will this do any long term damage? I have not been shifting with the button and have let the computer shift for me if that makes sense. I start off in M5 and let it do its thing. What are people's thoughts?

Anyone have a used Range?

Is there a max mph I should adhere to? When in L5?

KARNUT · August 16, 2022

8 hours ago, Cujoxx67 said:

Is there a max mph I should adhere to? When in L5?

I’ve spent most of my life pulling heavy from half tons to one tons. They when pulling would be in the next lower gear stick or automatic once transmissions had over three speeds. Once the engines got smaller and we got more gears it seems even empty they don’t stay in high gear long anyway. The RPM dance all over at the slightest incline. My CRV with the CVT transmission spends more time at 3K RPMS at 70 than 2K. Besides possible gas mileage hit and maybe more transmission heat that test would be interesting. Maybe you should start a thread. Something like who drives in the next lowest gear? What are the effects?

Edited August 16, 2022 by KARNUT

Cujoxx67 · August 16, 2022

2 hours ago, KARNUT said:

I’ve spent most of my life pulling heavy from half tons to one tons. They when pulling would be in the next lower gear stick or automatic once transmissions had over three speeds. Once the engines got smaller and we got more gears it seems even empty they don’t stay in high gear long anyway. The RPM dance all over at the slightest incline. My CRV with the CVT transmission spends more time at 3K RPMS at 70 than 2K. Besides possible gas mileage hit and maybe more transmission heat that test would be interesting. Maybe you should start a thread. Something like who drives in the next lowest gear? What are the effects?

I have been doing this for about 2 weeks now, with no obvious issues, keeping my speed below 80mph, usually 75-76mph. My rpms usually range between 2200 and 2500 sometime s bit higher, but no engine whine that I can detect. I'll do a few more weeks and update. Thanx for the feedback

KARNUT · August 16, 2022

9 minutes ago, Cujoxx67 said:

I have been doing this for about 2 weeks now, with no obvious issues, keeping my speed below 80mph, usually 75-76mph. My rpms usually range between 2200 and 2500 sometime s bit higher, but no engine whine that I can detect. I'll do a few more weeks and update. Thanx for the feedback

I have one car that is factory stock at 70 mph is at 4K RPMs in 5th gear it’s highest gear. It’s 22 years old.

Edited August 16, 2022 by KARNUT