Broken Motor Mounts

[Wolfbraid]

Well i just finished doing mine (07 4WD Yukon) Started at 3pm, I don't have the most organized tool box(seriously its a mess but I had everything)
I have two little distractions(4 and 7) running around, finally got the original mount out at 10pm, have it all buttoned up by 11pm, Put in the H3 mount, it practically fell into place, I had to disassemble the factory one to get it out, the heat-shield is a pain.

This isn't really a how to, because I didn't really follow one set of directions.
Removaleverything is 15mm)
3 frame bolts can be accessed from above(or wheel well)
4 engine block from below with creative extensions and swivels.(you can sneak an extension in some tight spots)

I jacked up from the reinforcement plate but also backed it up with a ratchet from above.

I didn't touch the diff, I removed the steering linkage(only firewall end would come off, if I got the whole thing out it would have be a little easier)

OEM mount still stuck in there, I flipped the OEM mount over, removed the two 15mm on the mounting plate, and took out the plate, heat-shield and then the mount.

Installation, the H3 mount just wiggles in, took a couple tries to figure out which side to put in first, then it almost drops right into place.
Reverse,
Hand threaded all 4 block bolts, and frame bolts.
2 of the block bolts can be tightened from wheel-well, the other two have to be tightened from underneath(at least with the tools I have)
all 3 frame bolts are easy to access from wheel well, front one needed final tightening from above

 

[Richard Blakely]

So I just returned from my mechanic after a routine oil change and he shows me I have a cracked drivers side motor mount!!!! WTF... I mean seriously GM? You would think they would install a strong enough motor mount for what people use these SUV's for. My mechanic ony works with GMC and Chevy's and he said he is noticing this often.

Has anyone else experienced this problem?

Oh and cause where it is located, not the cheapest of repairs either..

 

[Richard Blakely]

My 07 tahoe was severely jerking when accelerating from a stop. Suspected u joints but we’re checked fine. Talked to another Tahoe owner who experienced the jerk, and said the motor mounts need replacing to fix. Sure enough, the new motor mounts fixed it

 

[Bigkevschopshop]

Looks like I just joined the broken mount club. They are on their way out. Rough vibration at idle steadily gotten more pronounced. Last time I was at the dealer they said they were ripped but not broken yet. They are on that downhill fast. Waiting for cooler temps to do at least the drivers. Question how much more noticeable is the idle w h3 mounts? I know some say “seat of the pants”. I feel mine now mostly in steering wheel but don’t want to feel that shit. Got cammed vehicles for that sensation.

 

[kbuskill]

Looks like I just joined the broken mount club. They are on their way out. Rough vibration at idle steadily gotten more pronounced. Last time I was at the dealer they said they were ripped but not broken yet. They are on that downhill fast. Waiting for cooler temps to do at least the drivers. Question how much more noticeable is the idle w h3 mounts? I know some say “seat of the pants”. I feel mine now mostly in steering wheel but don’t want to feel that shit. Got cammed vehicles for that sensation.

I have H3 mount on drivers side and standard hydraulic mount on passenger side... I don't notice a difference from stock.

 

[iamdub]

I think if you can feel it depends on how smoothly your engine idles. Some idle smooth as silk (mostly well-maintained Gen3s) and others feel like they have an intermittent miss (a lot or most of Gen4s). Even if you can feel the slight difference in idle, it still feels much better than the clunk of a blown hydraulic mount. It's also much more comfortable than ripping open old scars when you end up replacing the hydraulic one a second or third time. Do it once and be done with it. I have no qualms with my H3 mounts.

 

[tgui]

My Gen IV 6.2 as a lumpy idle stock. I feel just a tad more vibration with the H3 mounts at idle over the stock mounts. Driving there is no difference.

 

[Wolfbraid]

I have H3 mount on drivers side and standard hydraulic mount on passenger side... I don't notice a difference from stock.

My H3 mount feels 1000X smoother than the broken one, not sure what stock felt like.)

 

[Meccanoble]

Just changed to H3 Hummer and my goodness, I love my truck again. I havent driven hard in so long, I forgot it had a V8. Just wanted to share some feedback on the process.

First, I planned to take off that steering stick thing but it would not come out for me. I didnt want to force anything. Looked at a video where someone just pulled up on one side but mine seemed to move but not enough to seperate. Wasted time.

I have the AWD so front DIFF was definitely in the way and prevented any work from underneath. I ended up taking the back half of the driver wheel for a different angle access but was able to do most of the work from above. Without removing anything besides the plastic rear well (dont even have to remove rim/tire), you can squeeze the mount out from the wheel well if you unbutton a connection or 2 or just hold them out the way. I had to unbolt the old one to make it 2 pieces to get it out. The stock Tahoe mount is definitely bigger than the H3 Hummer one, not just the aluminum part. I squeezed it in from same location as 1 piece successfully. BTW, I did not see an option where you could even seperate the H3 mount like you can on the Tahoe stock mount.

The hardest part seemed to be unbolting and installing the part of the mount farthest away from the front. But you dont need any special tools to do it from up top. Took a lot of patience to get that side done and was able to fully tighten from the wheel well side, not the top.

I was looking for more vibration or issues with this mount but seems very normal especially when you have been living with a bad mount for so long. Night and day difference! Best part, I dont have to worry about this being an issue for a very long time.

 

[Rocket Man]

Just changed to H3 Hummer and my goodness, I love my truck again. I havent driven hard in so long, I forgot it had a V8. Just wanted to share some feedback on the process.

First, I planned to take off that steering stick thing but it would not come out for me. I didnt want to force anything. Looked at a video where someone just pulled up on one side but mine seemed to move but not enough to seperate. Wasted time.

I have the AWD so front DIFF was definitely in the way and prevented any work from underneath. I ended up taking the back half of the driver wheel for a different angle access but was able to do most of the work from above. Without removing anything besides the plastic rear well (dont even have to remove rim/tire), you can squeeze the mount out from the wheel well if you unbutton a connection or 2 or just hold them out the way. I had to unbolt the old one to make it 2 pieces to get it out. The stock Tahoe mount is definitely bigger than the H3 Hummer one, not just the aluminum part. I squeezed it in from same location as 1 piece successfully. BTW, I did not see an option where you could even seperate the H3 mount like you can on the Tahoe stock mount.

The hardest part seemed to be unbolting and installing the part of the mount farthest away from the front. But you dont need any special tools to do it from up top. Took a lot of patience to get that side done and was able to fully tighten from the wheel well side, not the top.

I was looking for more vibration or issues with this mount but seems very normal especially when you have been living with a bad mount for so long. Night and day difference! Best part, I dont have to worry about this being an issue for a very long time.

Awesome news.

 

[SwaggerLikeBah]

Just did my drivers mount in my 2010 GMC Sierra Denali 6.2 with the OEM H3 mount. I had read all 53 pages of this forum before hand so I knew what was in store. Less than 3 hours start to finish. Floor jack with special wood 2x to lift on the front of the engine between the diff and the steering. Dealing with the fire wall side bolts was the biggest pain. Did all the work from above laying over the grill. Steering shaft out. Old mount slipped right out with enough engine lifting. H3 mount took a minute to slip in when I figured out which way it wanted to go. Hand tightened the block bolts. lowered the engine. 3 frame bolts went in without a problem. Buttoned everything up and done. Ribs bruised and hands cut up but saved the $500 or so doing it myself. Thanks to everyone who shared their experiences in here. Really helped 1000%

 

[Meccanoble]

Just did my drivers mount in my 2010 GMC Sierra Denali 6.2 with the OEM H3 mount. I had read all 53 pages of this forum before hand so I knew what was in store. Less than 3 hours start to finish. Floor jack with special wood 2x to lift on the front of the engine between the diff and the steering. Dealing with the fire wall side bolts was the biggest pain. Did all the work from above laying over the grill. Steering shaft out. Old mount slipped right out with enough engine lifting. H3 mount took a minute to slip in when I figured out which way it wanted to go. Hand tightened the block bolts. lowered the engine. 3 frame bolts went in without a problem. Buttoned everything up and done. Ribs bruised and hands cut up but saved the $500 or so doing it myself. Thanks to everyone who shared their experiences in here. Really helped 1000%

You not joking about bruised ribs. My chest cavity still pains me when I put pressure with my finger. I had to use some padding to protect myself reaching over that grille/bay half way through the install. Still feel some pain in my shoulders extending from driver wheel well to tighten bolts.

Make sure whoever does this install sets up enough wood stacked up to lift engine. I used 4 pieces of half inch MDF wood stacked on top of each other (top 2 about 3 inches long). I lifted from back end of oil pan. There is enough space to lift right next to the front sway bar but had car on ramps and the jack was maxed. Scared me because I thought it wasnt going to be high enough to slide the mounts in and out and already uninstalled the original. Thankfully it was still enough to get it all done.

 

[B2sdad]

I am going rogue on this one and going with the atomic poly mounts. Not worried about vibration at all, since my suburban is cammed and has extremely loud system in it. It vibrates enough as it sits.

 

[jrobie79]

Can someone provide the part # for the H3 mounts?

 

[iamdub]

Can someone provide the part # for the H3 mounts?

ACDelco 25847739. It's the passenger side for the H3, but fits both sides of our trucks. It's recommended that you replace both.

 

[B2sdad]

I agree with others, if you have the time and a few more proper tools, it will be much less difficult. For me I only had last night after work, and have a 2nd car if needed for the next few days, so I decided to attempt it, knowing if needed I could run to Walmart for tools. I have to go back to work this morning and family coming this weekend... and in temp housing currently, the circumstances are extenuating for me.

Bell housing was fine; I used a piece of steel to spread the load across the ribs of the bell housing. If you have it, a jack and piece of wood would be ideal. Your not lifting the truck with it, just the engine about 2/3 inch at most. I was careful and lucky. I was able to do it all without lifting the truck. Not recommended, but doable if in a pinch... just don’t jack the truck up from the bell housing... and don’t jack the bell housing with a tiny point on the jack.

I did it all from the top, there was just enough space to look through the side fender with out removal to see the bolts... those 4 bolts on the block... that will be the most frustrating part. If you have a flex extension this will help significantly. I decided to try without more tools, figuring by the time I ran to Walmart to get one I’ll be able to struggle through in the same amount of time. Be CAREFUL not to damage the wires especially the tiny one for the wheel speed sensor.

Getting the old one out was a puzzle, but bending the heat Sheild a bit (no worries there because your not using that anymore) and fidgeting it around you can get it out. A step stool will help reach it all... laying on the engine bay hurts sometimes. I used a moving blanket to cushion it a bit.

Theres a couple more vids out there, but this one gave me the courage to attack it. You can see this guys struggle with it and know what to expect. I was expecting a PItA so I was able to stay calm.

I’ve been a backyard/street/diy/“out of necessity” mechanic since I was 15 (now 32) doing things the hard way because it was the only way to get to work. Over the past years I usually have much more time and proper tools/lifts to get the job done, but this time I didn’t. After spending too much to have shop install engine mounts just 6 months ago, I was determined to do it myself. I tapped into those past “hard time” experiences to get through this one.

At least now a days I have a cell phone that doubles as a mirror, and can stick in places I can’t see to record video/pics of what I’m trying to reach (helps a lot for the 4 bolts on the block).

If I could do this in parking lot, at night, with only a 15mm socket, 3” and 1” extension, a pair of channel locks, the jack that came with the truck and piece of steel, and my mechanics gloves were a luxury.... most anyone could do this with a little more time & tools.

*not advocating or recommending to do it the way I did, just sharing the experience for knowledge to all.

But I couldn’t have done it without Tahoeyukonforum.

Well said Sir!

 

[ls1frc]

My 140k has the driver's side broken.

I bought the H3 mounts, but am having second thoughts. I really like the quiet interior and would hate if it added any vibrations.

 

[kbuskill]

My 140k has the driver's side broken.

I bought the H3 mounts, but am having second thoughts. I really like the quiet interior and would hate if it added any vibrations.

I have the H3 mount on the drivers side of my LTZ.... no regrets.

 

[iamdub]

My 140k has the driver's side broken.

I bought the H3 mounts, but am having second thoughts. I really like the quiet interior and would hate if it added any vibrations.

You likely won't notice anything, if there's anything to notice.

 

[tgui]

I have both H3 mounts. There is just a little more vibration, nothing like poly mounts I ran with atomic stuff. Personally I didnt give a shit with poly atomic mounts. Some things need to pass the wife test.....