Good Morning All,
I have a 2010 Maxima with the 3.5l V6 and CVT. I bought the car in pretty poor running condition. It had many vacuum leaks and a bad battery. I made quite a few small repair and got it running and driving well. I brought it back in to finish putting it all back together. I had it running for about ten minutes in the garage and the water pump began to leak. I knew it couldn't be that simple. Well, long story short, I took the engine out and ended up rebuilding it entirely. In putting the engine back in, I stripped out one of the Torque Converter bolts, so I replaced it with a junkyard Torque Converter. I also replaced both Transmission Filters and the CVT Fluid. After getting it all back together (again), I get p0868 (Transmission Fluid Pressure Low) and the vehicle doesn't move. When it is in Drive or Reverse and you press on the accelerator, the RPMs go up to 2000 and then drop right back down to 1500. It will steadily bounce back and forth between the two, but no movement. When in Park or Neutral, the vehicle will rev up as high as you want it to. I decided to replace the Torque Converter with a new one since I did use one from the junkyard, but still no joy. P0868 is the only code. I have adjusted the fluid level and it appears to be correct. Any input would be greatly appreciated!

 

The most likely culprit is the intermal screen you replaced. Some aftermarket ones look correct, but are a bit too long on the tube. Put the old one in or get a genuine Nissan screen.