Transmission Issue Help!

[phild1087]

Hey everyone! I'm new here, but I promise I've tried to search through the forums already, and I haven't quite found anything that syncs up to the issues I'm experiencing.

So, my girlfriend's 2001 Alero with the V6 is in question. Automatic. The car has roughly 225,000 miles on it. Obviously with that kind of mileage on it, you aren't expecting it to perform like a new car, but this seems like something is wrong.

Background: not long ago (within the past couple months) my girlfriend noticed that the car would not shift past 2nd gear one day on the way to work. She wisely pulled off and turned it off and had her car towed to her mechanic. He said that a line carrying transmission fluid had broken open/rusted out (don't remember which) and had leaked most of the fluid out. As far as they could tell, the transmission didn't suffer much damage, so they patched/replaced the line, filled it back up with fluid, and sent her on her way.

Now, though, the car is verrryyyyy reluctant when accelerating onto highways to shift from 2nd into 3rd and then 3rd into 4th. Again, this is only when you're trying to give it some gas, but when you do so, the RPMs will climb and climb and climb (I'm talking getting up to around 5000 RPMs) and the car will NOT shift. It will only shift if you back off the accelerator a bit, almost like you have to trick the car into shifting. And once it does shift, I don't hear anything, but there's a lurch and it does not feel like a smooth shift.

As far as we can tell, the car isn't leaking any fluid, and the engine still has plenty of power when it needs to. There's also no hesitation when down shifting if you need to accelerate, but it won't want to shift back up into the original gear.

We took the car back to the mechanic, and he said that he didn't notice anything that was out of the ordinary, but I've driven this car dozens of times over the past 2 years, and there IS something very different about how the transmission behaves. The car is old and has a ton of miles, and we're reluctant to have the whole transmission either replaced or re-done. So we're hoping this might not require anything super intensive to repair. The car is in pretty darn good shape otherwise.

I'm very sorry if this IS a common problem and my search skills are completely inept, but I would appreciate any and all help troubleshooting!

Thanks all!