I just picked up a 95 LS400. I test drove it a couple of days ago and all was good. I put some gas in today and drove about 7 to 10 miles to work. On the way home after about 15 miles thru traffic it started acting up with the rpms rising high but barely moving. I had to let it sit for an hour or so before it drove fine. Almost home and it started up with the same problem. I let it sit for 30 minutes, came back out and it was fine. All the gears slipped including reverse....what do you think?

 

Easiest thing to do now is check your fluid to see if you're low. If you're low, there isn't enough fluid in the torque converter for the stator to turn. Observe the fluid color and smell.

If fluid is fine, then my next suggestion is to check up on the torque convertor.