Broken motor mount

[Joseph Garcia]

Thank you for your quick reply, Randeez. My Denali is an AWD with stock manifolds.

 

[randeez]

yep same here (awd), changed mine out (with headers), the forward bolts to the block on both sides are the harder ones, they are angled right at the frame side of the mount. without the diff you can get them from under - not worth pulling diff just to change mounts though. just have an assortment of extensions diff lengths, wobble head socket not a bad idea.
i cut the heat shield up to get them off, makes seeing what youre doing easier and you'll have a better idea of how to get them back on. swapped mine to the poly atomic mounts they were pretty easy to get back in as the mounting bolts are more in the open, not shrouded by the heat shield

 

[Joseph Garcia]

Thank you for the additional information, randeez.

Can you clarify a bit more about your statement, "swapped mine to the poly atomic mounts they were pretty easy to get back in as the mounting bolts are more in the open, not shrouded by the heat shield"? I'm not clear on what 'atomic poly mounts' is referring to.

 

[Chrismnj]

I have change mine to H3 mounts and OEM Transmission mount while engine was out so it was easy for me, but can confirm they do fit perfectly.

Hummer GM OEM 08-10 H3-Engine Motor Mount Torque Strut 25847739

 

[kbuskill]

Thank you for the additional information, randeez.

Can you clarify a bit more about your statement, "swapped mine to the poly atomic mounts they were pretty easy to get back in as the mounting bolts are more in the open, not shrouded by the heat shield"? I'm not clear on what 'atomic poly mounts' is referring to.

Atomic is a brand and poly refers to the material they are made from polyurethane, which is stiffer than rubber.

The atomic mounts are essentially, almost, solid mounts.

Here is a link...

https://atomicfabandperformance.com/product/07-14-gmt900-poly-motor-mounts/



The passenger side H3 mount, that Chris mentioned above, is what alot of us run successfully.

The original mounts for our trucks are "hydraulic" mounts, meaning they are a rubber balloon/sack filled with oil to help reduce perceived vibrations. The problem is they have a tendency to tear and dump the oil, especially if you do any spirited driving.

The passenger side H3 mount is a solid rubber mount and is much more durable. It is used by ALOT of fleet maintenance garages maintaining the Police fleets. It fits both the passenger and drivers side of our trucks.

 

[08grey]

I have the atomic mounts. You will feel vibration after in the truck at idle. I have changed mounts more than I can remeber so it was a no brainers for me. I dont mind the vibration although I haven't experienced it with the ac running yet.

Sent from my SM-G973U1 using Tapatalk

 

[randeez]

Yep my idle is bumped up a bit already and is pretty smooth (750rpm is so), if I drop it down it gets pretty rowdy the closer to 550-600rpm with the cam and mounts lol

 

[Chrismnj]

I will take a pic of mine oem mounts after 45k, They were already wet at the base

 

[Joseph Garcia]

Thank you for the more detailed information, guys. Much appreciated, and I am understanding it.

I currently have what I believe to be a fair amount of vibration that I can feel right up through the steering wheel, whether at idle or during acceleration. That is one of the reasons that I am considering replacing the motor mounts.

I believe that the vibration became more pronounced after installing the Gibson extreme catback exhaust, but I have checked the entire exhaust line multiple times, and I cannot see any areas where it may contacting the truck's body or frame. Of course, I have 'pushed' the truck much harder, since installing the exhaust system and getting a Black Bear tune, so I may have damaged, or further damaged, the existing motor mounts, and contributed to the increased vibration.

I am not against having the additional vibration, as long as it is not the result of something beginning to fail, such as the motor mounts.

It appears that you have a preference for, and get good results, with either the H3 or Atomic Poly motor mounts. Is it simply personal preference at this point regarding which replacement motor mount to purchase, or are there some additional factors that I should consider, before making a final decision.

Please give me any additional thoughts that you may have, and again, I really appreciate your input.

 

[kbuskill]

Thank you for the more detailed information, guys. Much appreciated, and I am understanding it.

I currently have what I believe to be a fair amount of vibration that I can feel right up through the steering wheel, whether at idle or during acceleration. That is one of the reasons that I am considering replacing the motor mounts.

I believe that the vibration became more pronounced after installing the Gibson extreme catback exhaust, but I have checked the entire exhaust line multiple times, and I cannot see any areas where it may contacting the truck's body or frame. Of course, I have 'pushed' the truck much harder, since installing the exhaust system and getting a Black Bear tune, so I may have damaged, or further damaged, the existing motor mounts, and contributed to the increased vibration.

I am not against having the additional vibration, as long as it is not the result of something beginning to fail, such as the motor mounts.

It appears that you have a preference for, and get good results, with either the H3 or Atomic Poly motor mounts. Is it simply personal preference at this point regarding which replacement motor mount to purchase, or are there some additional factors that I should consider, before making a final decision.

Please give me any additional thoughts that you may have, and again, I really appreciate your input.

If you don't plan on doing a supercharger or turbo then the H3 mounts should be sufficient.

But if you are going FI then the Atomics are probably the better route. IMO