[thehemi]

I replaced my passenger side, after cutting it down 1/4". I could not replace the driver's side, though. The engine wouldn't jack up enough. Maybe part of the intake setup was hitting on the firewall, I'm not sure.

 

[miketexas]

I didnt have any problems the way I did it. I would replace both front mounts, theres no need really to do the rear transmission mount

In my experience, if you have bad motor mounts the trans mount is bad also. What may or may not happen if you don't replace the trans mount is that the front new mounts can raise up the motor and with the rear mount bad still, the angle of the power train is off and may cause the fan to rub the shroud. If it it doesn't then don't worry about it.

 

[bh29621]

I have to say thanks to all those who have contributed to this thread over the years

I just replaced both motor mounts in my 04 Envoy XUV. Just turned 100k miles and I had noticed a vibration on start up with the engine cold. I had considered the motor mounts and found this topic when I searched. The symptoms described here covered many of the same things I was experiencing.

I followed the instructions here, and really only deviated in getting to the driver's side top nut. I used and combination of both an 18 mm Gear Wrench and a pass thru or go thru socket. Didn't have to take the PCM off but I did loosen the 3 bolts holding the lower engine mount bracket to the frame (did this on both sides).

As others have noted, in comparing the old and new mounts (I did go with OEM parts) there was maybe 1/4 to 3/8 difference in height.....didn't seem like much, but what a difference. No more vibrations throughout the cabin on cold start and the engine seems more quiet while driving. Shifts also seem a bit smoother.

Great thread and thanks to all who contributed.

 

[BobbyA]

Just did both mounts in my 2008 Trailblazer I6 2WD. Took about 2 hours. Followed factory manual (MOL), removed sensor, unscrewed fan clutch from pump, removed the 4 nuts on the mounts. Used a tip from here about keeping one side captured but movable while jacking the other side. Heat shroud sucks ass trying to keep it over the keyway during reassembly.