I'm just looking for a little experience here. My tranny doesn't slip but seems to shift into 4th and 5th gear way too soon (4th at about 30-32mph and 5th 45-47mph) and only does so after car has driven about 5 miles or so, downshifting same thing (back into 4th about 42mph, back into 3rd 28mph), other than that car drives great. I've looked up codes in JTIS already seems very tedious and difficult to track down, just wondering if anyone has same issue and/or knows what it is.

 

I haven't noticed at what speed the car shifts but it's a little too soon for my taste. Generally if I don't want it to shift I just use the J-gate and keep it in a gear just a little longer. Try using the J-gate and leaving it in 4th around town and see if it helps. Just don't forget to shift up when you hit the highway.

 

Red, looking up your two fault codes, it would appear that your J-Gate shift cable has become misadjusted and what you are experiencing is the computer not seeing the tranny being completely in the D position. If it isn't that, then I would be looking at the range sensor for some form of electrical problem. If both of those check out fine, then you are looking at an internal failure of the tranny.