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hello i own a 05 pontiac bonneville 3.8  with a 4t65e and not too long ago it started slamming the gears sometimes it drives fine and sometimes it just likes to slam the gears. lets say your driving and it starts to slam the gears you stop and kill the engine and you let it seat for couple minutes and most of the time it goes back to normal.

fluid its normal, no check engine light, vehicle has 150,000 miles but it seems that transmission has been replaced.

my question is it posible that any of the valves in the valve body its getting jammed and that is the reason that tv pressure its at max only sometimes?

my other question is i replaced the filter and fluid with syntetic fluid dexron vi do you thing that could be the cause of the problem?  

hang in there.. several transmission gurus will stop in soon.

transmission codes are in the P0700 to P0799 range  

Get the computer scanned for codes. The computer is sensing a problem that is causing it to increase line pressure in the transmission. The codes will point to the problem.  

there is no codes in the computer that means there is no sliping on the transmission or problems with any circuit. this is more like something mechanic something getting stock or dirty  

What kind of scanner did you use? If you cant get any codes then the car has to be driven with a quality scanner hooked up in data  mode so solinoid and sensor data can be monitored while the problem is occurring. The fact that the problem goes away after you shut off the key and restart it means that it  is a electronic control issue. There is no throttle valve in that trans. The computer controls line pressure based on vehicle speed and throttle position sensor data. The pressure solinoid itself is known for going bad on those trannys too.  

http://www.youtube.com/watch?v=1HloCxl-bKY  

thanks bvan for that video of your one car rally race up in Agua Dulce, CA



oh.. if you feel like OHMing the solenoids and sensors...


Here are the resistance specs on the internal solenoid
Connect Pins   Solenoid         Resistance at 68*F   190*F
A-E                1-2 Shift Solenoid               19-24      24-31
B-E                2-3 Shift Solenoid               19-24      24-31
T-E                TCC/PWM Solenoid             10-12      13-15
C-D                EPC Solenoid                       3-5          5-6  
S-V                Input Speed Sensor        893-1127 1132-1428
M-L                TFT Sensor                    3164-3867  225-285
                     Output Speed Sensor             981-1864  

ill be replacing the pressure solenoid this weekend, i talked to 5 different transmissions shops yesterday and 4 told me that is highly posible that the pressure solenoid its acting up cause they have replaced plenty of those so ill give it a try

thanks for your time guys.  

sorry for the late response henri_60, but yeah, changing the EPC (pressure control solenoid) will probably correct your problem.  They fail often and many times do not generate a code.