4L60-E Transmissoin Problems

My Transmission is not working to well in reverse. It will shift into reverse but you can't go more than just a little above idle when it will start to slip, but if you build up speed up slowly its ok. All forward gears are ok. Any ideas what the problem might be.

Check the fluid level. Reverse is the first gear to go when the fluid is low.
Chris

Fluid lever is ok. Changed it not too long ago. Looks like i'm going to have to get it fixed.