[xcopterdoc]

I'm showing 4.5 to 5.5 hrs labor for removal and reinstallation of the tranny plus .5 for each expansion plug. Use a 50/50 mix or water and antifreeze. I would also recommend a complete coolant system flush now that you have put those pellets in there. Get that crap out of there ASAP! Also, I'd have them do all the expansion plugs in that area that require the removal of the tranny... you dont want to go thru this again in a couple months.

 

[xcopterdoc]

I dont see how they were ripping you off.. 400 bucks is about right depending on the labor rate. Those radiator stop leak products are trouble. They plug up radiator cores, heater cores, ect. After the leak is fixed have the system flushed and get it out of there. There's no such thing as mechanic in a can. The ONLY solution to a coolant leak is fix it, permanently!
Also, especially with older vehicles, some busy shops dont want the headache of messing with them. So they will give a high estimate to drive you away. Then they go on with business and doing the gravy jobs.