I have a 2002 Monte Carlo SS. I've owned it for about 10 years. It has apx. 155,000 miles on it. The problem I'm having is this. When the car is cold you can stomp the gas and go no problems. but as soon as she warms up you come up to a stop light or slow down under 15 miles an hour ,put your foot on the gas to go and it will spit and sputter and jerk you to no end. and dont even think about going up a hill.. take your foot off the gas and then foot back on the gas get up over 25 miles an hour and it runs just fine. I have just discovered that if i shift manually. Starting in first ,tach at 2 shift to second, tach at 2 shift to 3rd, tach at 2 go to drive she runs and shifts like a dream. can anyone help me figure this out. i just replaced the map sensor and it didnt help at all. the computer read out says the following..
code 0481 Coolant Fan Relay 2 control circut
0742 torque converter clutch (TCC) System stuck on
1811 Maximum Adapt and long shift

 

You have some pretty concerning transmission issues that we couldnt diagnose fully, here. Sounds like the car is forcing itself into limp mode to prevent further damage and using the shifter bypasses that.

I think the only option is take it to a trans shop. It sounds internal. Youre at just the right mileage that these 'prone to failure' transmission usually fail.

 

so is this where i say that it 's been doing what ive been told is a hard shift for the entire time i've owned this car. and so want to just believe that my baby is just having growing pains and you do a belly roll laugh..???
i just gave the codes that dealt with what i thought was the transmission problem. theres still 6 more codes for the anti lock brake system. which again its all from when i bought the car in 2015.
i love my car. but she isnt cheap..
thank you so much for helping me.

 

I'd agree with whtmonte, this isn't something that can be remotely diagnosed properly - especially not with multiple issues going on at once. You need someone to tap into the live data while driving and step through diagnosis steps to isolate the causes. That could include electrical diagnosis via the harness plug depending which way things go.

The very high mileage also convolutes things. For the 1811, that's almost always a simple pressure control solenoid on a newer transmission. But with that kind of mileage, you've got clutch wear, valve body wear, seal wear, and accumulator wear that could also be a cause or contributing factor.

Two things:
-I wouldn't just keep driving it broken like you have been. Its very likely youre accelerating wear and tear and could turn a cheaper issue into a major one.

-I'd be very prepared for either a full rebuild or a new transmission. As whtmonte mentioned, you're certainly in the failure zone for mileage on these. IMO the failures start popping up around 100-125k and by 200-225k the vast majority of originals have failed (excluding v8 cars of course). So I wouldn't at all be surprised if a shop diagnosed it and deem it needs a full rebuild.


If you're dead set against paying diagnosis (which I presume is the case if its always been like this) amd just wanting to take one last shot in the dark, Id:
-Pull the side cover and replace the 4 solenoids (1/2, 3/4, TCC, and PCS). Don't bother checking them electrically, they can still ohm out correctly but can act sticky / be slow to act.
-Drop the bottom pan and install a shift kit on the accumulators. There's one made by Transgo that is intended to help with this kind of issue without being as harsh as a performance shift kit.
-Drain the fluid (which you'll have to do for the above anyways), install a new filter.
-Drive it a little (to mix up the fluid with the old stuff that can't drain out), then drop the pan and dump the fluid again.


If that doesn't work, it almost certainly needs a rebuild as that's about all you can replace externally without pulling it and tearing it apart. This is of course assuming none of your other codes you mentioned are causing an interaction with the transmission.