I have notice over the past month or so, I'll be driving normally, not even fast. Where I'll feel what Im not sure is a slip or not. I'll be as detailed as possible. Lets say I'm doing 70mph on cruise control. I'll give it just a lil bit of gas to pass another car, no more than 5-10% throttle most days. At 70mph im usually at 2400-2500 rpms cruising and its jump a few hundred rpms for a sec and feel a slip or a small "thud", but then continue to accelerate normally. I look at my scan-gauge to see that i'll be at 20-30% throttle when this will happen. This is only at around 70 mph. Also this isn't every time, it is very inconsistent. Other than that, the car drives fine and typically shifts nice and smooth. From 0-75 mph at 30-40 % throttle she'll shift fine all the way through. Just a lil background, in February, I had a new 4th gear clutch shaft installed. Has driven fine since. Since I don't know exactly what it is, I've been rather gentle with the car so I don't cause more damage or speed up whats already going bad. I'd guess its a trans issue, but I figured i'd get some other opinions too.