So, its a 2009 SS with 103K. Transmission fluid and filter were changed about 6 months ago. Dexron VI and wix filter. Pan and magnet were clean. Fluid level checked hot and is in upper cross hatched area on dipstick. Car has been running great and no problems with tranny until a couple of weeks ago. I get what feels like slipping in first or maybe a sloppy hard shift into second. It only happens when car is cold and I'm pulling out of my steep driveway. As I'm going uphill it feels like its slips briefly in first and then clunks back into gear. It only happens that one time when I'm going up the steep driveway and drives normally from there on. I've tried to replicate it on a incline when its warm but it wont do it. I even parked overnight at the top of my driveway to see if it would do it on level ground and it wouldn't. I double checked fluid level again thinking that it wasn't picking up when on a steep incline but it still reads on the upper cross hatch on dipstick. I'm not getting a CEL and I cant find any codes with my blue driver or diablo tuner. I've flashed back to stock tune to see if it makes a difference but it did not. I've also tried it with traction control off but no difference. I was thinking PCS but I'm not sure. Currently I am stumped and open to any input.

 

I'm going to have to lean toward the pressure switch manifold in the transmission. I rebuilt a 4l60e at 202K miles due to a broken forward sprag. It had the same issue and I believe it's what caused the broken sprag. I think you have a 4t65e which is basically a transverse 4l60e with a few enhancements to make it a bit stronger. Even after the rebuild the problem persisted. The only related part that I didn't replace during the rebuild was the pressure switch manifold. I dropped the pan and replace the pressure switch manifold and the problem was resolved. It's starting to do it again at 328K miles so I may drop the pan and replace it again.

 

Yeah, I'll probably pull the side cover off this weekend and replace everything. Looks like I can get all the solenoids and manifold switch for about $150.
Thanks.