Transmission.
 

I recently had my tran changed (in another state)and months later I'm told by my friend an ex mechanic that some kind of screw that hold the trans right in the middle of the engine toward the front, needs to be tighten. He made me park the car and shift back and forth and we could see how when I did it and with the hood open, the entire trans was moving back and forth and I shifted, sometime I almost feel like when I shift the entire car jolts and shifting is sometime very hard.

So: How difficult is this? Should i change that screw? why is it loose? does it have anything to do with shifting being so hard sometimes?
thanks

Hard to tell from your description, but maybe it's the front engine mount? The mount itself could be broken (the rubber block inside the mount comes apart) or the bolts could be loose where the mount bolts to the engine/tranny.

If the engine mount is loose, it'll allow the engine/tranny to move & cause a clunking noise.

it sounds to me as well that it is the frt motor mount bolt(s) loose .also you might want to chk the rear mount to make sure that it is not broken

How hard is it to replace/tighten the front mount?

Here's the mounts, this really depends on which one is broken or loose, and WHY it's loose.
http://www.hondaautomotiveparts.com/...13SM40_B47.gif
In the best situation, there's a couple bolts for you to tighten. Easy.

It's possible that the rubber inserts of any of these mounts is broken. The rear mount is vacuum-operated, and difficult to reach because it's buried.

In the worst situation, you might have threads stripped out of the engine block. That's more work, and our advice would depend on your experience of doing that kind of work.