Transmission going? Help!

My transmission jerks into first and second gear..it has no third or overdrive. The back end made a huge popping/thumping sound when I let off the gas pulling into my driveway.
I have no knowledge of transmissions and what makes them tick. What could this be and for the love of Pete, do not tell me it is going.

Dont like to be the grim reaper.. but its going.. matter of fact its gone.. dont drive it until you get another or it might leave you..

I've been waiting for it to leave me for awhile now. I knew the transmission was going to go before the engine since like last year.
Damn this car..should have sold it for the SS...

should have sold it for the SS...
Yes, you should have :wink:

Yes I should have...
But the strange thing is..it didn't do it this morning. It shifted fine and had the 4th gear, not the 3rd, and had overdrive. The back end made no sounds as well.
Could this be a senor or something that made it do this or is it really just falling apart?

i doubt it...transmission dont usually heal themselves...if they do they are just waiting for a very inconveniant time.....

Best thing to do is go to a reputable transmission shop and have them look at it. They will probably drive it and can drop the pan and take a look. Thats the only way your really going to know anything. Especially if you dont know anything about transmissions. What your describing doesnt make much sense to me. Not that I claim to be an expert on transmissions but if you have a 700r4 or 4l60e, I dont think that the converter will lock in 2nd gear. Maybe im wrong. Id still say take it to a shop.

the converter should only lockup while the tranny is in top gear and your cruising

Actually, a 4L60E will do a TCC lockup in third, depending on the programming.

I havn't had a problem with it since then. I added some fluid because it was low and it has been running fine since.