2000 GMC Jimmy Transmission Leaks

Look underneith the jimmy at the transmission. Where is the leak coming from? Sounds like a blown front seal. Were you doing brake stands or burnouts? Where ever the leak is, in order to leak 3 quarts out it has to be undriveable. Have it towed to a repair shop or repair it where it is parked. What ever you do--do not run the engine until this problem is fixed. If you do (or did for over 2 minutes or so) you mine-as-well replace the transmission or have it rebuilt. A tranny with 140000 miles on it cannot take the punishment that 3 quarts low dishes out. All the sounds you hear are the clutch bands and shifting solonoids crying- starving-for fluid. By the time you hear this it is usually too late.

Sorry about the delay in responding--
You can get a new factory rebuilt transmission with a factory warranty for a lot less than a new vehicle. You can also have your transmission rebuilt, which is be cheaper than a factory rebuilt. I suggest having your transmission rebuilt by a good transmission shop like cottman transmission. Sometimes a rebuilt, or factory rebuilt transmission is better than the origional; because as your type of trans. Evolves, GM finds weak spots and makes emprovements and upgrades that rebuilders know about.
My opinion is that if you like the blazer then I would get the trans. Rebuilt. I would not just get it fixed, get it totaly rebuilt.