Cant go over 30 mph!

Hello,
I recently purchased a 2001 Impala, welcome to the club huh?, the issue is that a few weeks into driving the car it began to have some issues. The car cannot accelerate over 20 mph without making a grinding noise and it cannot go over 30 mph at all while on "D". The same thing for "1" and "2", however, when I put it on "3" it can go up to about 55 mph. I 100% thought it was the transmission, but I read a few posts online and saw some people saying it could be the mass air intake, others saying it could be the fluid and that I should flush it, and others saying it could be a mal-functioning cat. converter. So now I am more confused than ever, if I take it to the mechanic they're going to ask what do I think is wrong and when I say I think it's the tranny - that's what it's going to be because well they hear a cash register going CACHING! Well thank you in advance for the help.

Also says it can be the bands need to be adjusted or the fluid pump.

HELP ME, PLEASE!

You need to have it scanned for trouble codes . Most of the major auto parts chains will scan it for free . When you have a code , you likely will have a better idea of what is wrong with your Impala . Take the code and go to www.obd-codes.com . You can then see what the code is telling you and go from there . Good luck !

Also says it can be the bands need to be adjusted or the fluid pump.

HELP ME, PLEASE!

as was mentioned get the DTC failure codes pulled and post here.

seems you do have transmission problems . these transmissions required synthetic transmision fluid but DEXRON III was used and with no fluid replacing every 40,ooomi they failed at a high rate. just after the 36,ooomi warrantee period.

I would go to a transmission shop to have them get the drivetrain codes and do a pressure test. with that info they will be able to tell you whats going on. my guess a 2,ooo.oo rebuild.

thats just a guess. could be a simple valve failure etc..

if the fluid is dark and has a bad burnt smell its gonna cost ya.

You need to have it scanned for trouble codes . Most of the major auto parts chains will scan it for free . When you have a code , you likely will have a better idea of what is wrong with your Impala . Take the code and go to www.obd-codes.com (http://www.obd-codes.com) . You can then see what the code is telling you and go from there . Good luck !

No engine light and no code showing up - took it to AutoZone.

as was mentioned get the DTC failure codes pulled and post here.

seems you do have transmission problems . these transmissions required synthetic transmision fluid but DEXRON III was used and with no fluid replacing every 40,ooomi they failed at a high rate. just after the 36,ooomi warrantee period.

I would go to a transmission shop to have them get the drivetrain codes and do a pressure test. with that info they will be able to tell you whats going on. my guess a 2,ooo.oo rebuild.

thats just a guess. could be a simple valve failure etc..

if the fluid is dark and has a bad burnt smell its gonna cost ya.

Now that you mention it, it does smell bad - kind of like burnt oil but I thought that was another problem completely.
I thought it would take a pretty good stab at my pocket book.

To add confusion to the puzzle; my wife attempted to turn it on - two seperate occassions - and it would not start. HOWEVER, just a few hours ago, I turned it on fine and drove it past 40 without a problem - I had to slow down and stop due to a stop sign. I do not want to push it too hard because it's the first time it goes over 40 on "D" so I don't want to mess it up more. So now I am really puzzled.
I explained the problem to a guy in the shop, he said it could be my Transmission's speed sensor but we could not replicate the problem because it was driving fine now. WTFudge!?
:confused:

if you read my post earlier it says go to transmission shop for diagnosis. pressures//drivetrain codes.

auto zone can only get engine codes and possibly some other codes. drivetrain codes require an expensive OEM type.