I have a 2000 Monte Carlo SS, 3.8 non supercharged. Im not sure about what model transmission is in it (i dont know if they used different ones in different years). Anyway, the car seems to "slip" a little between the 3-4 shifts. It only does this under light acceleration and only between 3rd and 4th gear. The rpms jump up about 300 rpms before it shifts. It does not shift slow though, it seems to be fine except for the little bump in rpms between gears. I have a 1 ton diesel with a 4L80E in it and it did something similar to this, but it was because of the way the torque converter locked up and was normal. Just wondering if this is a problem or something "common" haha. Thanks, tyler

 

Check your transmission fluid. You have a 4t65e transmission. The 3-4 shift is your torque converter. If you have the correct amount of fluid, change the fluid and filter. If problem persists, you'll probably have to replace a solenoid, or the TC itself. Good luck!

 

ok cool thanks!