Broken Motor Mounts

[kbuskill]

Hey All,

I've read enough to know to go the H3 route! My 2008 Yukon Denali RWD's passenger mount is bad...but the driver's side is completely fine?? I thought usually it was the other way around? Maybe the driver's was replaced by a previous owner (I've owned it for 25k miles, it now has 97k on it). I can't see a part number on the driver's mount, other than a circle with a "15" etched on one side. I did the brake test... In drive, no engine movement; in reverse, the passenger side jumped up 3 inches. I get a lot of vibration at idle, but no other symptoms. So the question: do I just replace the passenger now with an H3, replace both now with H3's, or wait til the driver's fails, then replace both with H3's?

Go ahead and replace both now.... it's not my money or labor... lol

 

[wjburken]

Hey All,

I've read enough to know to go the H3 route! My 2008 Yukon Denali RWD's passenger mount is bad...but the driver's side is completely fine?? I thought usually it was the other way around? Maybe the driver's was replaced by a previous owner (I've owned it for 25k miles, it now has 97k on it). I can't see a part number on the driver's mount, other than a circle with a "15" etched on one side. I did the brake test... In drive, no engine movement; in reverse, the passenger side jumped up 3 inches. I get a lot of vibration at idle, but no other symptoms. So the question: do I just replace the passenger now with an H3, replace both now with H3's, or wait til the driver's fails, then replace both with H3's?

Have you been launching in reverse? According to @Rocket Man , that can have catastrophic results.

Seriously, though, I’d replace both sides. They have the same number of miles on them.

 

[Rocket Man]

Have you been launching in reverse? According to @Rocket Man , that can have catastrophic results.

Only if you have FI!

 

[wjburken]

Only if you have FI!

Well, there is that one small whipple detail.

 

[22YukonDenali22]

Have you been launching in reverse? According to @Rocket Man , that can have catastrophic results.

Seriously, though, I’d replace both sides. They have the same number of miles on them.

Yeah I can't help but peel out in reverse, throw the e-brake, 180, throw the automatic lever into drive, then scream 15mph down my quiet neighborhood street! Life in the fasttt laaaane

 

[Rocket Man]

Yeah I can't help but peel out in reverse, throw the e-brake, 180, throw the automatic lever into drive, then scream 15mph down my quiet neighborhood street! Life in the fasttt laaaane

I had an excuse lol. But it ended up snapping the housing on the front diff and destroying a cv joint. Not recommended. But one of my forward launches snapped the output shaft on the trans when it hit second gear so wtf.

 

[22YukonDenali22]

I had an excuse lol. But it ended up snapping the housing on the front diff and destroying a cv joint. Not recommended. But one of my forward launches snapped the output shaft on the trans when it hit second gear so wtf.

Dang! What a bummer!!

 

[Tozan]

Man why did I read this thread? Now I need to go check my 197k mile Tahoe to see if my mounts are broken...

 

[bsmith901]

Glad I came across this thread! I checked my 2007 Yukon XL 5.3 motor mount and sure enough it was bad. Although I’m at 160.5K miles I’m convinced it has been broken for a good while, having noticed what I thought was slack in the yoke/differential for some time. I replaced both sides with the suggested Hummer style mounts last weekend. Things are now back to good and tight feeling upon acceleration. Driver side install was no problem, right side was a bit of a challenge but I got it done! Back to my original plan, I installed an improved left valve cover and did a little PM, installing fresh belts, idlers, and plugs. Coolant refresh and new hoses are ready to go the next available weekend along with adding a cabin filter. Appreciate all the good info from everyone here that led me to checking the mounts!

 

[Tozan]

Man why did I read this thread? Now I need to go check my 197k mile Tahoe to see if my mounts are broken...

Hmm... I guess I need to remember to check this...