1985 Lincoln town car making clicking/tinking noise

I am so frustrated! I have a 1985
Lincoln town car hearse. Of the
various issues I have with it, there is
this awful clinking/clicking/tinking
noise coming from underneath the
car in the front. It almost sounds like
little rocks tinking around under
there. It only happens when I've
driven for about 5 minutes, and most
when I am moving forward.
Sometimes at a stop I hear a similar
buzzing noise coming from the same
area (not the fuel pump).

Basically what I can say is what I
know. I know one of the motor
mounts is bad. I know that there's
something up with the transmission,
as it makes a squeaking noise when I
start out from a stop, then goes
away. It has a pretty bad shudder
and some gears are worse than
others. In reverse, if the wheel is all
the way turned, I hear a very loud
clicking noise and BOOM, the car
stops. That has to do with the
column shifter slipping, though. Also,
I have a brand new exhaust and
carrier bearing, so I don't think it's
that, however I am 99% sure the u-
joints are bad.

I also suspect the cats are bad.
Jimmy has a little bit of a power
issue, and he's doing pretty bad on
gas these days. I was wondering if
someone could give me an idea,
based on this information, of what
could possibly be wrong. I feel like
I'm on a wild goose chase and I
don't know where to start. I am
currently in an automotive program,
but this is way beyond my
experience. The clicking noise has
gotten worse lately, and today while
at a stop light, I heard a loud clunk
just while I was sitting here, from the
same general area. If someone could
give me an idea of places to start
looking, I would really appreciate it!