Hi everyone. I have an 03 Monte Carlo with a 3800V6, auto. im having an issue with the transmission and really need some help.
when first starting out driving, the car drives and shifts great, but once its warmed up, it shifts Hard in all gears 1-2,2-3,3-OD.
I don't have much money to spend on taking it to the garage so any advise will be very helpful! Oh, and its had a trans flush and the filter changed at no avail, and both 02 sensors were replaced. so far, nothing.

 

Is it the stock cat? Sounds like a clogged cat if it's happening only when warmed up.

If you run the car for a while and climb under to look at the cat you can tell if it's bad if it's glowing red. Also, you can get the pressure tested at an exhaust shop.

Let us know what you come up with

 

how hard is it shifting? its not slipping right? maybe the previous owner put a shift kit in or something, my monte has always shifted well enough to notice, it doesn't SLAM into gear but but shifts hard and tight like it should... alot harder than older cars shift if thats what your used to

 

I was also going to suggest getting the Cat pressure tested

 

Actually, Last night I went out and plugged my OBD2 in and even though the engine light wasnt on, I got 3 Codes;
1- o2 sensor sensor 1 bank 1 circuit malfunction
2- o2 sensor heater curcuit malfunction
3- torque converter clutch stuck on

its obvious that the torque converter code has to do with why it shifts hard, and by hard I mean it seems to "slam" into gears through all gears 1-2,2-3,3-OD.
but like I said it doesnt do that until it was driven a good 15 minutes.
Does it sound like the o2 sensor would have anything to do with it?

 

The o2 sensor tells the PCM along with the MAF how much fuel to dump, the transmission is probably telling the PCM to go into fail-safe mode from the torque converter problem.

You said the transmission was flushed, was it hooked up to a machine and back-flushed? That could have done the damage to the converter

 

The transmission was drained and the filter was changed and it was refilled after the Trans problem started, but doing that made no difference.
The o2 sensors would have nothing to do with the transmission right?

I was told that even a small exhaust leak would trigger the o2 sensor to malfunction? is that true?

As far as the transmission goes... Is there any way to clean the torque converter clutch solenoid by using TransX or any other tranny additive? The code reads "Torque converter clutch stuck on" so im kinda wondering is there something I can do to get it Un stuck? basically I want to know if there is anything besides the solenoid itself that would cause that to be "stuck on" such as a faulty relay or possibly a faulty ECM thats telling the tcc solenoid to stay "on"?
I am trying to go through all other possibilities before I go and have the tranny taken apart and the solenoid replaced. Big hole in the wallet.

 

Hi everyone,

Just wanted to update everyone on the "TCC Stuck on" issue.
Here is a list of everything I have tried:
-fluid and filter change
-checked/tested all fuses that relate to the transmission
-bought a haynes repair manual and followed the complete transaxle wire diagram.
-tested brake/TCC switch for circuit interuption when brake peddles depressed

Basically, Ive tested absolutely everything up to the transmission with no avail. I have concluded that the problem is either the trans fluid pressure valve faulty, the TCC release switch, or the PCM.
The only thing left to do is decide whether I want to fix, or sell.
Thank you all for the advise!!

 

You didn't have a code p1811 did you? This is the PC solenoid and would explain the hard shift.

 

No P1811 code, but get this... I believe that I have a electrical problem somewhere. The airbag light on the dash is on all the time, and there is no seatbelt light. even when I just turn the key to on "but not start" no seatbelt light. The guy who owned it before had put in a aftermarket radio, and he told me he was having problems with the radio cutting on and off, I havent had that problem myself...Yet! Maybe this has to do with the o2 sensor circuit malfunction and TCC circuit stuck on malfunction? I really dont know how to pin point an electrical problem. Any ideas?