I have searched the internet and found nothing. I have some issues. First it is a 02 2500HD, 6" Fabtech lift, 36" super Swampers, 216k miles.. I haven't had any issues until recently. When I put in reverse it will back up if there is no load, like backing up on pavement. If I back up in sand or have the wheels turned and step on the gas it revs like in Neutral and makes a high pitched grinding noise. OR it will feel like the rearend bounces and hops popping in and out of R. I have taken it easy since this issue started and planned to have it looked at. Drove it today to get taxes done and it started reving up and losing Over Drive. The ABS light, Airbag Light, and Brake Light in the dash all came on. The speedometer jumped up and down from 45 to 65. Needle Kinda bounced up and down 20mph or so as the transmission felt like it was trying to engage OD. If I accelerated it would be fine until I let off and OD tried to kick in. Wouldn't hold speed at 45 - 60mph without reving and kicking in and out of OD. At a stop light it idled fine, accelerated fine, shifted fine 1st to 2nd to 3rd. RPMs didn't spike with the speedo jumping. The trans temp wasn't hot. I scanned it when I got home, no codes. Fluid is fine, doesn't smell burnt. I checked both fuse boxes and fuses seem ok. I am puzzled, any help is MUCH appreciated. Thanks in advance!!