Rough Idle = New Motor Mounts?

[JerseyGMC]

Maybe i should consider myself lucky. I was having the same issue with vibration at Idle.

Just picked up my truck from the dealer after them having it for 2 days, they replaced the motor mounts with the new upgraded desgn , and the truck idles smooth as glass now. 

Truck has 8500 miles and had the vibration since the day i bought it. I will post an update after i put some miles on it to see if it has solved the issue for good.

[2017Z]

Would you mind posting the service order details showing the parts and labor. If this works I want to go to a different service shop and have them do this but never heard there was a “new” design. 

[2017Z]

Mine is going to new GM service on Thursday. I drove with a tech and rep and both agreed it’s rough. 

 

Any my chance you can post the part # or details on what they used. Or even your dealership that maybe they can call for advise. I’d like to pass as much on to the new place that they can hit this out of the fate right. 

[Justin101714]

The engine mounts. No doubt about it. I just did 2 sets today. They are liquid filled mounts. They are getting internally grounded inside the mount and causing too much vibration through the frame. Very easy to see on a picscope. E1 and E2 vibration frequencies all day long with these trucks. Get the mounts done and it will go away.


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[hirdlej]

12 minutes ago, Justin101714 said:

The engine mounts. No doubt about it. I just did 2 sets today. They are liquid filled mounts. They are getting internally grounded inside the mount and causing too much vibration through the frame. Very easy to see on a picscope. E1 and E2 vibration frequencies all day long with these trucks. Get the mounts done and it will go away.


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Can we get the part numbers for the updated mounts?  I would just rather buy them and change them out myself. Thank you in advance!

[Justin101714]

I’d had to get it off of the boxes tomorrow. I honestly can’t remember what they were. I think they are listed in the bulletin. #17-NA-166


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[hirdlej]

8 minutes ago, Justin101714 said:

I’d had to get it off of the boxes tomorrow. I honestly can’t remember what they were. I think they are listed in the bulletin. #17-NA-166


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Looking forward to those part numbers. Did you notice a dramatic difference right away with the new mounts?  I would imagine they only get better as they break-in.

[Justin101714]

Instant fix for all the trucks and SUV’s I’ve done. Smooth idle right away. By the way, any one planning to do these. I always do them from the bottom, GM suggest removing the exhaust manifolds.....no way! It’s tight coming out from the bottom but it can be done. The right side, remove the starter it clears up a bunch of space. You’ll want to jack the engine up as high as you can get it. Pretty much the catalytic converters will be touching the vehicle body. It doesn’t stress any components or harnesses either. I should get a video next time I do a set.

 

 

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[hirdlej]

I plan on doing mine in the driveway.  My local dealer I wouldn't trust with an air filter change so that's why I'm just going to do these myself.  I plan on pulling the fender liners then loosening up trans mount, both motor mounts and I haven't decided if I should remove manifolds or loosen up the y-pipe.  I'll probably do manifolds since I don't have a hoist but that's no big deal. 

Where would you suggest jacking the engine up by?  My truck is 2wd.  I'd love to see a video if you made one!

[20165.3Eco]

Glad to head this from someone with experience. My truck fits the description of the rough idle bulletin exactly. Rough idle in neutral more rough in drive after it's been running for a while. Reverse and it is almost 100% gone but you can still feel it running. 

[Justin101714]

I normally just use a 2x4 with a screw jack on the oil pan. I’ve had the exhaust touching the body before. It’s pretty high up, enough for the mounts to clear but it is still mighty tight. The mounts are shaped weird.


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[Elk Hunter]

Good info in this thread. Bought my truck about 10 days ago with 18 miles on it and noticed it right away. I've put about 800 miles on and will be taking it to the dealer to let them fix it. Drives me nuts, brand new truck shouldn't be doing this. Justin if you get a chance to post the P/N of the mounts that have worked for you that would be awesome!

[MD11G200]

I have 6.2 with this problem, they installed the new mounts, no fix, any suggestions?

 

[2017Z]

An update. Got the mounts changed out last week under the TSB and absolutely no change. They did an idle reset as well but it still idles at 490. Shakes and has the almost die feeling still after the truck is warmed and come to stop in drive.  Service said bring it back. Not sure what that will do since this “fix” did not fix it. Not sure how those who claim here the change out fixed it but no go in my 17. 

 

Im convinced GM has no fix for this. They will kick the can down the road until the trucks are older model year and out of warranty and never fix it.  

 

 

Edited March 1, 2018 by 2017Z

[MD11G200]

I am convinced there is no fix for this or the transmission shifting problems. Unfortunately someone who either doesn’t understand the problems or fabricates a statement and acts like there problem was fixed and doesn’t follow up when they discovered they were wrong and don’t really have a clue. Well it’s a forum not sure why I thought I could find a fix here, that’s my fault and frustration.Thanks for the follow up.