Engine mounts broken - clunks?

The rubber part of my engine mounts are broken. I will replace them with the nice Black Dog mounts when I can. In the past I've had a really loud clunk up front on the driver's side when going over rough railroad tracks at speed. Could the engine be moving enough to cause that? I always assumed it was something in the suspension (all old and rusty too).

Should I be ok to drive it carefully for a while until I get some new mounts and come up with an engine lift?

Thanks

no need for a engine lift for mm's, a floor jack will do, id be real carefull as the engine moving could make the fan go into the radiator

Yes, bad engine mounts will make clunking noises.

Drive very carefully until you replace them. If your Jeep is a stick, take shifts very easy... I put the fan through the rad on a quick shift with bad engine mounts.

No need for an engine lift. A regular floor jack and a block of wood is all I needed.

also, unless someone started a new company, it's BROWN dog.
if you have the 2peice style motor mount, your engine DOES move around... but that sounds like a worn control arm bushing, or a loose trackbar bracket. replace the mounts, and if it still persists, have someone turn the wheel with the jeep running, while you sit in front of it watching for clunks.

Thanks for the replies. I had it in my head that the oil pan probably shouldn't have all that weight on it, but it sounds like it would be ok? The clunk was severe and only happened on one particular set of tracks if I hit them at full speed (25-30mph).
I'll take it easy and start saving for mounts. Anything else I should know?

There are brackets that bolt to the engine, and the mounts attach to the brackets. Those bolts like to fall out and/or break, check them.