Slight shutter......

[KMeloney]

The shudder could be coming from a failing torque convertor........ you are feeling it disengage.

Can you tell me more about this? Aside from a low rumble, I got a "chugging" sensation on deceleration @ 3500-3000 RPMs, like the truck doesn't know which gear to be in. Could that be the torque convertor? And if so, is something like that checked with a scan tool, or is it more of a mechanical (as opposed to an electrical) issue?

 

[Goodinblack]

Well....hard to tell via the internet...........

However, though "mechanical", one could hook up a Tech 2 to the truck and go for a drive.

While driving you could command the convertor to lock and unlock via the scan tool........around the suspected RPM....... and see if it does the described complaint on demand.

My 2009 Suburban sometimes has that chug like feel to it too.......I took it in 2 times for it........they said it was normal..... I have the stock tune and I just live with it.

The Converter going feels more like a jittery shudder.

If a transmission has actual slippage, then usually it sets a DTC code, and raises the line pressure. Increased line pressure results in firmer shifts overall.

 

[KMeloney]

Well....hard to tell via the internet...........

However, though "mechanical", one could hook up a Tech 2 to the truck and go for a drive.

While driving you could command the convertor to lock and unlock via the scan tool........around the suspected RPM....... and see if it does the described complaint on demand.

My 2009 Suburban sometimes has that chug like feel to it too.......I took it in 2 times for it........they said it was normal..... I have the stock tune and I just live with it.

The Converter going feels more like a jittery shudder.

If a transmission has actual slippage, then usually it sets a DTC code, and raises the line pressure. Increased line pressure results in firmer shifts overall.

Thanks for the reply, Lee.

 

[Goodinblack]

From my CB Radio.

 

[AZSCTACO]

I have a hypothesis that I wanted to see what all your thoughts are. I noticed this morning when I get the shudder/rumble, the Tahoe is in V4 mode while I'm slowing down....then when I hit that certain speed (around 10-15 mph) and RPMS are around 600....I get the rumble/shudder and then goes away when it switched back to V8 mode. Could this be the issue? Hope that makes sense....

 

[KMeloney]

I have a hypothesis that I wanted to see what all your thoughts are. I noticed this morning when I get the shudder/rumble, the Tahoe is in V4 mode while I'm slowing down....then when I hit that certain speed (around 10-15 mph) and RPMS are around 600....I get the rumble/shudder and then goes away when it switched back to V8 mode. Could this be the issue? Hope that makes sense....

I need to check how it relates to 4 vs 8 mode, but I'd say that that's the case with me, too. In a previous post, I said that it happens are very slight throttle input. What I was probably experiencing was the input being not enough to kick into 8 cyl mode, and that when it does kick into 8 cyl mode, the rumble/shudder seems to go away. So, your scenario makes sense.

Not sure what it all means, but I think we're experiencing the same thing...

 

[Goodinblack]

Well......on my 2011 Yukon XL........I CAN feel it switch in between modes, and it is rather pronounced.

On my 2009 Suburban, I have to look at the dash to tell if it is in V4.

Both trucks are LWB 2WD.

 

[AZSCTACO]

Well......on my 2011 Yukon XL........I CAN feel it switch in between modes, and it is rather pronounced.

On my 2009 Suburban, I have to look at the dash to tell if it is in V4.

Both trucks are LWB 2WD.

That's what got me thinking about the V4 to V8 change this morning. I was watching it on the dash and sure enough.......

 

[rickh925]

I know this is an older thread, but I was given a 2007 Tahoe LTZ from my father-in-law. It had 295K miles on it then and has 306K now. It has developed this same shudder and it is definitely tied to the v4/v8 transition. It shudders while slowing, even if brakes are not being applied, while in V4. When it transitions to V8 around 10mph or so the shudder goes away. While in V4 slowing and the shudder is present, if I bump the gas a little to force it to V8 the shudder goes away. If I put the tranny in neutral while slowing, no shudder at all.

I'm just starting to look for this issue and am a little panicked as we are heading out of town Christmas afternoon for an 800 mile trip.

From past experience with other vehicles, it definitely feels like a torque converter not releasing or something like that.

Has anyone found the definitive answer to this?

Thanks
Rick

 

[AZSCTACO]

I know this is an older thread, but I was given a 2007 Tahoe LTZ from my father-in-law. It had 295K miles on it then and has 306K now. It has developed this same shudder and it is definitely tied to the v4/v8 transition. It shudders while slowing, even if brakes are not being applied, while in V4. When it transitions to V8 around 10mph or so the shudder goes away. While in V4 slowing and the shudder is present, if I bump the gas a little to force it to V8 the shudder goes away. If I put the tranny in neutral while slowing, no shudder at all.

I'm just starting to look for this issue and am a little panicked as we are heading out of town Christmas afternoon for an 800 mile trip.

From past experience with other vehicles, it definitely feels like a torque converter not releasing or something like that.

Has anyone found the definitive answer to this?

Thanks
Rick

It definitely has to do with the AFM and changing from V-8 to V-4 mode. Right after I got a BB tune I had the AFM shut off so it stays in V-8 mode all the time and that shudder is completely gone.