I finally got under the car this morning and was able to remove the two engine bearer bolts from below (one per mount) thereby technically freeing the engine from the frame.

However, when I attempted jacking the engine up with a piece of 2x4 under the oil pan, the whole chassis began lifting up along with the engine.
I do not understand how that is possible...I need someone to help me figure out why the whole chassis lifts up along with the engine. With the two engine bearer bolts removed, the engine should be lifting up from the frame, freeing the side mounts so that they can be replaced with the new ones....but the whole car comes up when jacking up the engine via the oil pan.

Why is that?

By the way, when I first looked (not to closely) at the front mount, I reported that it was pretty much gone. However, taking a close look today, there is no front mount and front mount assembly to speak of under my car. The whole thing is gone - and there is no lower or upper strap, the whole front mount assembly is just not there... many thanks to the PO or whoever left this situation unattended to before him.
It's amazing to me that I could drive this car this way for the seven years of my owning it. Unfortunately, I did not even know that something was missing and should be there before learning about engine mounts these past few days, so I did not do anything until now to take care of it.

I'd appreciate it if someone here can help me figure out why the engine is not lifting from the chassis after removing the two engine bearer bolts. I looked very closely and nothing seems to prevent the engine from going up. Could it be that the rear engine mount (transmission mount) needs to be released as well? Nobody who has replaced the side mounts has ever mentioned in this forum having to do that, as far as I remember what I've read so far.

I'd appreciate some help with this...thanks.

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1979 240D, W123, 105K miles, stick, white w/ tan interior.