Ok, so I have a 2001 Grand Prix GT with the 3.8 and the 4T65E tranny and it's throwing the P1811 code. The symptoms have been present since I bought the car almost 3 years ago at around 188K miles (now 217K) the car shifts fine and grabs fine in cold weather and even in hot weather up until it heats up. In winter when it's cold the symptoms almost never happen, it's rare, but in hot weather during the summer the problem is ever present especially once the car heats up. It shifts hard between all gears, shifting up and down. However before the car heats up in the summer the shifts are smooth but long which is what is causing the tranny to max out line pressure and throw that code. I changed the fluid twice (within a two week period to be sure I got all the crud out of the system) and replaced the filter about 25K miles ago (a little after I bought it) and the fluid wasn't too terrible, considerably dark, maybe a brownish maroon and just a tiny bit of build up on the bottom of the magnetic pan. Tranny fluid now is still a shade darker than new and no build up or anything on the dipstick. I've read a ton about this code and that the PCM (pressure control module) could be the problem. Tons of people having the same symptoms and saying that replacing the PCM has basically solved all the issues, however I'm also reading that replacing it isn't a gaurunteed fix which I'm fully aware of, especially with how long I've let this problem go thinking the transmission was just going out. I want to just have a shop replace the PCM and I hope that fixes the problem however the one thing I am concerned about is that during the summer especially, from a stop if I give the car too much gas it shudders pretty bad and feels like clutch slippage, (sometimes no slippage at all, still more often than not.) and every now and then the shifts aren't hard it just shudders between the shift which makes me think the clutches are in fact worn and tranny might just need to be rebuilt. I am wondering if there is any correlation between this specific symptom and the P1811 code. Like if it's possible that the bad PCM could not only be causing hard shifts but could also be causing clutch slippage of any kind. I realize the car has a ton of miles and a rebuild would in fact be the best thing regardless of what's wrong with the PCM. I just don't have the money to spend on a new tranny or a rebuild, especially since the cost of either is more than the car is even worth at this point. Any information or input from someone who knows better would be much appreciated.
