Time for new engine mounts?

[jsoltren]

My new-to-me 2013 GMC Yukon XL 2500 has 100k miles. At idle - at stop lights - the vibration is bad enough that I need to shift from drive into neutral to calm things down.

I got a video this morning of the engine at idle. I shifted R-N-D-N in 2WD and 4WD-LO a few times. In D in 4WD-LO it looks like the engine maybe moves half an inch. Service manual spec is to replace at one inch of movement.

I got under the truck and can't really tell if the mounts are cracked or not. There is a heat shield in the way.

Thoughts?

 

[GranPrix]

Make sure you get the Hummer H3 mounts

 

[GranPrix]

part# 25847739

 

[jsoltren]

I've heard that before. The stock mounts are fluid filled and maybe offer more damping but are more likely to break, is that right? I understand the H3 mounts are solid. They seem to be well regarded in some other threads.

 

[jsoltren]

Seems like H3 mounts are the way to go. I may just do the driver's side mount for now. It's usually the one to go, and, easier to change out.

https://www.tahoeyukonforum.com/threads/broken-motor-mount.110748/ was super helpful here.

 

[iamdub]

My new-to-me 2013 GMC Yukon XL 2500 has 100k miles. At idle - at stop lights - the vibration is bad enough that I need to shift from drive into neutral to calm things down.

I got a video this morning of the engine at idle. I shifted R-N-D-N in 2WD and 4WD-LO a few times. In D in 4WD-LO it looks like the engine maybe moves half an inch. Service manual spec is to replace at one inch of movement.

I got under the truck and can't really tell if the mounts are cracked or not. There is a heat shield in the way.

Thoughts?

I saw nothing in that video indicating excessive movement, but I also don't think you were giving it any throttle. It sounded like you were just shifting between the gears.

When the stock hydraulic mount first goes bad, it will rupture and leak. You'll see what looks like rusty water drained from it, ran down the frame and cross member and dried, leaving rust-colored chalky trails.

*Edit*
Does the 2500 even use the hydraulic mounts? If so and with it being new to you, the previous owner or dealership could've cleaned off the frame and mounts and may have even replaced them. Mine were really bad but I never really had any vibration issues. I don't think the engine should even be vibrating badly enough that blown or firmer mounts would be uncomfortable. Either you're really sensitive to engine vibes or your engine is idling rougher than it should.

 

[jsoltren]

It may be a rough idle. This one definitely has more vibration at idle than my 2001 Denali - which had pretty much the same engine.

 

[petethepug]

If the mounts haven’t been replaced in 100k miles, replace all 3, period. The solid rubber mounts for the 6.0 will go for another 100k when replaced as a set. Not sure if the hydro mounts from the 6.2 will fit the 6.0 mount brackets. All rear mounts are solid.

If one or two are replaced, not so much good will happen. The weakest mount always taxes the newest mount while trying to preserve itself. Same engineering as when replacing front, rear or all four wheel shocks. Nobody installs just one shock, bodda book, bodda boom.


Sent from my iPhone using Tapatalk

 

[BG1988]

My new-to-me 2013 GMC Yukon XL 2500 has 100k miles. At idle - at stop lights - the vibration is bad enough that I need to shift from drive into neutral to calm things down.

I got a video this morning of the engine at idle. I shifted R-N-D-N in 2WD and 4WD-LO a few times. In D in 4WD-LO it looks like the engine maybe moves half an inch. Service manual spec is to replace at one inch of movement.

I got under the truck and can't really tell if the mounts are cracked or not. There is a heat shield in the way.

Thoughts?

it's pretty common for the 6.0 to vibrate randomly
even the hybird 6.0 does it.. it's computer related issue...it feels like it's going to stall out..
putting it in M6 mode and driving for a 1/2 mile (then shift back to drive)makes it go away...

I suspect it's radio-frequency interference.. using M-MODE Changes the computer parameters there for "resetting the computer"


since the shaking occurs AT the same location every time, but not elsewhere.. in my city..

this is an important fact since it only happens at a very specific location...

 

[jsoltren]

I checked around a couple of other forums. There have been a bunch of reports of the LY6/L96 having a rough idle. Every now and then cleaning the MAF sensor leads to an improvement.

I'm wondering too if my '01 Denali had viscous mounts.