Original Post:
I have a leaking transmission in my 84 glt. When using on a daily basis there is no problem (It will just use a very small amount of fluid). However, if the car sits more than one day, It will leak like a pig. I have to add approx 2 quarts of fluid to get it back on the stick. From looking underneath it looks like it's leaking between the engine and transmission. I find a long straight line of fluid on the ground after the car sits for over a day. If my assumption is correct that it needs a new gasket between the engine/tranny, what is a fair price to pay for this service at a garage? Thanks in advance for any input. Jon

Update:
I apologize for the long interum between posts. The 84glt got put on the back burner for a while. Anyway, I'd like to say that the return lines to the tranny cooler were to blame. I could not hardley belive it. I took the bolt off the bracket holding the two lines to the tranny and felt around. Could not feel any holes on one, but the other I could feel just a slight ridge and I saw fresh fluid comming out. I proceed to hacksaw off both the lines where they connnected to the transmission. One had no noticable leak but the other had about a 1/8" wide by 1/4" long hole in it. I repaired the lines with rubber fuel lines and hose clamps. Total cost of repair was about $6. Absolutely no more leaking. Hard to belive this small of a hole would spew about 2 quarts of transmission fluid after setting a day or two. Thanks to all who replied with advice and I hope this helps someone else.
Jon