Can you hear this V4 to V8 sound? - Page 2

LesserO2Evils · 07-05-2016, 04:49 AM

I dont ever hear it as much as I FEEL it in my car. I am super smooth on the throttle while cruising, and the constant 4-> 8 transition drives me crazy.

jimmypop13 · 07-05-2016, 04:28 PM

I couldn't hear anything in the video however my first exhaust had a chirp/squeak during the v8/v4 transition that came from the afm valves. They replaced the whole exhaust due to the NPP rattle. The new exhaust never chirped

ReFLeX135 · 07-08-2016, 09:15 PM

I've compiled a video that catches all of the chirps/screeches/grinding much better. I think it's much more clear. Currently the car's at the dealership but I haven't heard anything back yet.

Getting up to speed and coasting, no shift = screech
Manually downshifting from 4th to 3rd to 2nd to 1st = screech/grind
In manual mode, no shift, and applying throttle from a lower speed = grinding

raptor5244 · 07-08-2016, 11:28 PM

Quote:

Originally Posted by ReFLeX135

I've compiled a video that catches all of the chirps/screeches/grinding much better. I think it's much more clear. Currently the car's at the dealership but I haven't heard anything back yet.

Getting up to speed and coasting, no shift = screech
Manually downshifting from 4th to 3rd to 2nd to 1st = screech/grind
In manual mode, no shift, and applying throttle from a lower speed = grinding

Well, you should be able to rule out the AFM valves by just switching to manual mode. AFM does not engage when the trans is in manual mode. Furthermore, you could bring up the page on the dash that shows the v4/v8 display and see if the noise corresponds with the mode change.

jimmypop13 · 07-09-2016, 01:22 AM

Quote:

Originally Posted by raptor5244

Well, you should be able to rule out the AFM valves by just switching to manual mode. AFM does not engage when the trans is in manual mode. Furthermore, you could bring up the page on the dash that shows the v4/v8 display and see if the noise corresponds with the mode change.

AFM does engage exactly once in manual mode. Once you switch gears after it comes on, it won't come back on at all until you're back to auto

ReFLeX135 · 07-09-2016, 04:15 PM

Yeah in my original video I had the v4/v8 screen on. It seems to happen when it switches. This would be the first two screeches in the newest video, where it seems no shifting occurs. Manual mode shifting I did twice, so that wouldn't be the AFM for sure. I just really hope they don't tell me it's normal..

raptor5244 · 07-09-2016, 11:00 PM

Quote:

Originally Posted by ReFLeX135

Yeah in my original video I had the v4/v8 screen on. It seems to happen when it switches. This would be the first two screeches in the newest video, where it seems no shifting occurs. Manual mode shifting I did twice, so that wouldn't be the AFM for sure. I just really hope they don't tell me it's normal..

For what it's worth I don't hear anything or feel anything when transitioning from v4 to v8 mode. The only way I know is by looking at the v4/v8 mode on the dash.

If it is the valves making the noise you can test it. There is a separate fuse that controls the AFM valves. You can pull it and drive. The car will still switch to AFM mode but the valves obviously won't close. However, be aware that when you are in v4 mode with the AFM valves closed the exhaust will sound bad, which is why we need them. Furthermore, unlike the fuse for the rear NPP valves, pulling the AFM NPP fuse will cause a CEL.

Has the dealer performed the TSB that calls for them to spray dry slide lubricant into the valve assemblies?

LesserO2Evils · 07-11-2016, 04:00 AM

Quote:

Originally Posted by ReFLeX135

I've compiled a video that catches all of the chirps/screeches/grinding much better. I think it's much more clear. Currently the car's at the dealership but I haven't heard anything back yet.

Getting up to speed and coasting, no shift = screech
Manually downshifting from 4th to 3rd to 2nd to 1st = screech/grind
In manual mode, no shift, and applying throttle from a lower speed = grinding

Oh....WOW!!!! Yeah, I have non of that. Sure hope I dont, either. Im sorry bud...

ReFLeX135 · 07-22-2016, 04:49 PM

Just an update. The dealer said all of my transmission problems and noises, AFM/exhaust squeaks and screeches, are normal. They drove other 16 Camaros that had the same problems, which are "by design"...

Wonkymom · 10-31-2017, 10:29 AM

When mine goes from V4 to V8 especially slow speeds on slight inclines I hear this annoying almost backfire “poof” sound - anyone else?? Or is that normal (dealership thinks so of course)

JaxChris · 11-01-2017, 09:29 PM

Automatic transmission? That sound is the forward AFM exhaust valves (under your front seats) popping open. If it were a cylinder activation issue, you would hear the noise through the top of the dash because the rear cylinders are the ones that turn on and off (against the firewall). The open of this thread, his first video sounded very much like those valves activating. In his second video he didn't show a good DIC screen to contribute to what could be happening and it sounded like a squeak with headphones on, so it could've been a steering rack noise because it happened coming out of a turn both times.

Chutzpah · 11-02-2017, 07:34 AM

My car has the same scraping sound transitioning from V8 to V4. In mine, it’s definitley the afm valves causing the noise.

cskipgo · 08-19-2019, 05:32 PM

Any updates? Did everyone get theirs fixed, or silenced at least?

Having the same issue with my 2019.

ws2186 · 10-09-2019, 01:50 PM

Im curious what can be done also. Mine sounds like a bad exhaust leak whenever its in V4 mode

07-05-2016, 04:49 AM	#15
LesserO2Evils GM repeat offender... Drives: 16 2SS Join Date: Dec 2014 Location: Grandview, Texas Posts: 1,474	I dont ever hear it as much as I FEEL it in my car. I am super smooth on the throttle while cruising, and the constant 4-> 8 transition drives me crazy. __________________ '16 2SS, Summit White. A8. MRC. NPP. Ordered:09/03/15. Received 12/22/15 INCOMING: ‘22 ZL1, Satin Steel. A10. PDR. Ordered: 03/02/22.

07-05-2016, 04:28 PM	#16
jimmypop13 Drives: 2016 camaro ss Join Date: Oct 2010 Location: Spring, TX Posts: 1,127	I couldn't hear anything in the video however my first exhaust had a chirp/squeak during the v8/v4 transition that came from the afm valves. They replaced the whole exhaust due to the NPP rattle. The new exhaust never chirped __________________ 2016 camaro 2SS hyper blue/Kalahari, A8, MRC, NPP, sunroof, SW headers through axleback, Circle D 3600rpm TC, Pray ported IM/TB, E85 Sold: 2002 Z28, NBM, M6, 460rwhp, 2009 HHR SS RIP : 2002 WS6 Black, A4, 355rwhp

07-09-2016, 04:15 PM	#20
ReFLeX135 Drives: 2017 Camaro 1SS Join Date: Jun 2014 Location: Lansing Posts: 114	Yeah in my original video I had the v4/v8 screen on. It seems to happen when it switches. This would be the first two screeches in the newest video, where it seems no shifting occurs. Manual mode shifting I did twice, so that wouldn't be the AFM for sure. I just really hope they don't tell me it's normal.. __________________ Hyper Blue \| A8 \| NPP Dual Mode Exhaust

07-22-2016, 04:49 PM	#23
ReFLeX135 Drives: 2017 Camaro 1SS Join Date: Jun 2014 Location: Lansing Posts: 114	Just an update. The dealer said all of my transmission problems and noises, AFM/exhaust squeaks and screeches, are normal. They drove other 16 Camaros that had the same problems, which are "by design"... __________________ Hyper Blue \| A8 \| NPP Dual Mode Exhaust

10-31-2017, 10:29 AM	#24
Wonkymom Drives: 2016 Camaro 2SS Join Date: Mar 2017 Location: Wisconsin Posts: 7 View My Garage	When mine goes from V4 to V8 especially slow speeds on slight inclines I hear this annoying almost backfire “poof” sound - anyone else?? Or is that normal (dealership thinks so of course)

11-01-2017, 09:29 PM	#25
JaxChris Drives: '16 2SS GD1 MX0 NPP F55 IO6 Join Date: Jun 2013 Location: Florida Posts: 1,298	Automatic transmission? That sound is the forward AFM exhaust valves (under your front seats) popping open. If it were a cylinder activation issue, you would hear the noise through the top of the dash because the rear cylinders are the ones that turn on and off (against the firewall). The open of this thread, his first video sounded very much like those valves activating. In his second video he didn't show a good DIC screen to contribute to what could be happening and it sounded like a squeak with headphones on, so it could've been a steering rack noise because it happened coming out of a turn both times.

11-02-2017, 07:34 AM	#26
Chutzpah Drives: Wild Cherry LT1 Join Date: Dec 2016 Location: Massachusetts Posts: 1,925	My car has the same scraping sound transitioning from V8 to V4. In mine, it’s definitley the afm valves causing the noise.

08-19-2019, 05:32 PM	#27
cskipgo Drives: 2019 2SS A10 Shadow Gray Join Date: May 2014 Location: SoCal Posts: 210	Any updates? Did everyone get theirs fixed, or silenced at least? Having the same issue with my 2019.

10-09-2019, 01:50 PM	#28
ws2186 Drives: 1968 Camaro Join Date: Feb 2016 Location: Riverside, CA Posts: 16	Im curious what can be done also. Mine sounds like a bad exhaust leak whenever its in V4 mode

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