I take my transmissions to a local lube shop that does a proper fluid exchange (not a flush, per se). Valvoline lube shops do it this way also. It's less hassle, cleaner, and I know it's a complete replacement with fresh fluid. Never had a problem in years of doing this with probably 10 different cars and trucks. It's worth doing it, in my opinion.As I'm thinking through all of this, should I be concerned at all about changing the trans fluid? If memory serves me right, I've probably done 1-2 trans flushes along the way. Now that I've learned the actual service vs flush is the right way to go, should I be ok on this? There are no issues with the transmission at all today.
Second question - I read that some people are using the engine mounts from the Hummer. Is this a better alternative?
On the engine mounts, yes and no. They're a solid mount vs the fluid-filled original mounts, so they last forever but they also transmit slightly more engine vibration to the frame. I have the Hummer mounts on my 2012 with the more aggressive cam and I can feel it at idle whereas I couldn't before I changed the mounts. It's not annoying to me but it is noticeable. My wife can tell the difference so she prefers to drive our '07, which is all stock and smooth like butter.