Can anyone tell me what the symptoms of a broken engine mount are?

I posted this a while back, but can't find an explanation.

I have a 99 2wd that has a two inch spring lift on the front and KYB MonoMax all round. She ran fine for a couple of years and then I let my son drive her for a bit ... big mistake! Anyway, when accelerating uphill, just before spool up, the front end appears to bounce. It's not the suspension. Could it be a broken engine mount? It is pretty violent when it happens, forcing me to let off the pedal and reapply slowly. It seems to only be under heavy acceleration, uphill. I see it a lot when getting onto the freeway ... any ideas?

 

Sounds like transmission clutches or torque converter slipage.

 

Please don't tell me that! I had tossed that around, but, since I don't have issues under hard acceleration on level roadway, I discounted it ... could this be true?

 

You should be able to see all that transaction if you open the hood, E brake on (maybe ) service brakes too) and give the go like you are going. You know, engage the clutch in gear and watch the eng. If it moves much more then a bit ..then that would be the ans.
As I recall thee is a through bolt in there that will stop it from going too far.