Broken Motor Mounts

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Rocket Man

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My Yukon is finally back on the road. My impressions on poly mounts are as follows...

I personally feel vibration when in D stopped at a light. I feel it through the brake pedal, the cab vibrates a bit, my bad side mirror shakes. We'll see what the wife says. Please note I set my idle high to deal with bad oem mounts and engine shaking. I'll put it back to stock. This might help considerably. I'm too tired to do it now.

Also note I have 160k miles on my engine with what appears to have been owned by someone that hates maintaining it.

When moving everything feels like stock. Like totally stock. I can hammer it and the engine stays in one place. No more headers hitting the body, O2 sensors hitting, or touching the starter wire. No more loud clunks. I had to tune IN more trans torque management on down shifts because I would get loud banging. Perhaps these mounts will mitigate that?

Do I recommend them? God yes. Many times over. GM has a serious ******* problem with their OEM fluid filled mounts. H3 mounts might work well too but when you have tight header clearances they might still allow hitting on the body. Please remember my Yukon has the 6.2, is tuned and will have a supercharger. I can't imagine H3 mounts lasting with large amounts of torque.

My overall recommendation is that if you replace your mounts, do headers while you're there. Even shorty headers. Or have bolts break like me and just do a long tube setup. ;)
The H3 mounts should be fine with high HP or torque applications just like my oem mounts on my NBS with my blower, cam and headers. Solid rubber mounts have been fine for built engines forever, it’s just the stupid fluid filled design that have problems.
 

tgui

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The H3 mounts should be fine with high HP or torque applications just like my oem mounts on my NBS with my blower, cam and headers. Solid rubber mounts have been fine for built engines forever, it’s just the stupid fluid filled design that have problems.


Thats a really good point.


I'm afraid my poly mounts did not pass the wife test. I personally don't mind them. This morning was a barrage of questions centered around whether or not the yukon was dying. We use my Yukon for family and trips.... so I'll try the H3 mounts next.


Does the H3 part "25847739" fit BOTH drivers and passengers side?
(Found the answer, yes!)
 
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tgui

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I got the wife out of the yukon and had a chance to hoon about. Goddamn these mounts keep things planted. I was able to do some AWD launches. She felt good. Its the first time I've been able to really use the power the long tubes/tune/high flow cat added. I know rocketman is laughing. LSA supercharger some day for me. With my sub going (something my wife ALSO hates), I couldnt feel much of anything vibration wise.

Ah well. If the H3s are good I'll just mount these Atomic poly mounts on the wall. They're pretty. If ever I get really stupid with power I'll swap em back in.
 

tgui

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H3 mounts are in.

I measured heights with calipers. H3 mounts are about .5 inches shorter than OEM. Thats not bad. More room for long tube headers. H3 mounts are much smaller so this will be an ok swap.

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tgui

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I retuned my engine and lowered the idle back to stock and spent time driving to break the poly in. Ok I don't know if poly breaks in.... Whatever...

Cabin vibration is greatly reduced. It still vibrates but now I find it livable. Mostly when stopped at a light in drive. Idling parked is fine. Driving is fine.

2nd round wife test in the next few days. Sorry for the neurotic posts. Perhaps I'm looking to convince myself not to go through the pain of doing engine mounts again.

I'm very lazy.
 

Rocket Man

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I retuned my engine and lowered the idle back to stock and spent time driving to break the poly in. Ok I don't know if poly breaks in.... Whatever...

Cabin vibration is greatly reduced. It still vibrates but now I find it livable. Mostly when stopped at a light in drive. Idling parked is fine. Driving is fine.

2nd round wife test in the next few days. Sorry for the neurotic posts. Perhaps I'm looking to convince myself not to go through the pain of doing engine mounts again.

I'm very lazy.
Well it's not a fun job from what I hear. I have read quite a few posts on pt.net where they say it's " barely noticeable" from stock, which I find hard to believe so it's nice to hear an honest opinion here where perhaps the person doesn't feel pressure to go along with the group. Myself, when I heard the Hummer mounts work, my decision was made if the ones in my 08 Silvy go. I could see these (poly/solid) being the go-to when the only other option was the original fluid-filled pieces of crap.
 

tgui

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Well it's not a fun job from what I hear. I have read quite a few posts on pt.net where they say it's " barely noticeable" from stock, which I find hard to believe so it's nice to hear an honest opinion here where perhaps the person doesn't feel pressure to go along with the group. Myself, when I heard the Hummer mounts work, my decision was made if the ones in my 08 Silvy go. I could see these (poly/solid) being the go-to when the only other option was the original fluid-filled pieces of crap.

Thanks. I stand by my assertion Atomic mounts are amazing. If I weren't married and in my 20s there would be no question of me not using them. Right now I'm at a light vibration in my seat and stereo wire rattle behind a door card at a light. Not bad to me. I am also guaranteed no problems even compared to the more stout h3 mounts.

I'm closing in on 40 and married. No kids luckily, they cost too much. Still I have older people considerations.

I even added an Atomic sticker to my GMC Yukon Denali Canyonero STi Type-R edition.

U56zWgx.jpg
 

Rocket Man

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Thanks. I stand by my assertion Atomic mounts are amazing. If I weren't married and in my 20s there would be no question of me not using them. Right now I'm at a light vibration in my seat and stereo wire rattle behind a door card at a light. Not bad to me. I am also guaranteed no problems even compared to the more stout h3 mounts.

I'm closing in on 40 and married. No kids luckily, they cost too much. Still I have older people considerations.

I even added an Atomic sticker to my GMC Yukon Denali Canyonero STi Type-R edition.

U56zWgx.jpg
That's the perfect example of anti-debadging lol.
 

kbuskill

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Thanks. I stand by my assertion Atomic mounts are amazing. If I weren't married and in my 20s there would be no question of me not using them. Right now I'm at a light vibration in my seat and stereo wire rattle behind a door card at a light. Not bad to me. I am also guaranteed no problems even compared to the more stout h3 mounts.

I'm closing in on 40 and married. No kids luckily, they cost too much. Still I have older people considerations.

I even added an Atomic sticker to my GMC Yukon Denali Canyonero STi Type-R edition.

U56zWgx.jpg

I've got all the badging off my Burb if you can find something cool to spell with it... LMAO

You could make it an URBAN canyonero... lol
 

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