Cadillac Repair: 93 seville rattilng, rattling sound, cheapo

Question
So if the rattling is cause by a transmission mount does that mean that it is a loose transmission mount, or is it just bad.  Also if that is the case, about how much does a trannsmission tune up cost.
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-----Question-----
0n my 93 seville that has only 74,000 miles, it has started to make a rattling sound when accelerating, that feels like it is coming from the around the transmission, but it only happens sometimes, so i'm a little confused on what it could be.  What do you think the problem is, and how can it be fixed?
-----Answer-----
Sounds like a transmission mount, but you can get a transmission tune up or dump some lucas transmission fluid in there.

Answer
A tranny tune up shouldnt be more than $140 but will probably only cost you $80-90. The cheapo alternative is some $10 lucas fluid restorer, ive never seen it fail, but this stuff is like honey and merely hides the problem but does not solve it.

The mount could be loose, dont count on it though. It's probably cracked.