too much line pressure?
 

What are the down falls to having too much line pressure in the transmission. What would cause excessive pressure besides the transmission tune?

Edit:
I guess that it would help to state that the transmission is a 4L60E in a 2001 Camaro. It developed a small leak from either the convertor which has been in for approximately 200 miles, or the front seal, which was not replaced when installing the convertor.

The reason that I am asking about line pressure is that the manufacturer of the convertor said that it might be cracked due to excessive line pressure. I am guessing that several other things would have failed prior to the convertor cracking.

Thanks

What kind of transmission?

Well assuming a 60E the tune mostly only affect part throttle presures and idle max presure is a mechanical function. As for what the down side to excessive presure well broken hard parts and drums. Excessive wear possibly with the engine thrust bearing.
The presure at Part throttle is bothe a mechnical and tuning system the tuning varies the line within the range of the the mechanical set up.