Check your differentials, front and/or rear. Sounds like they are slipping. In other words, the screw that keeps tension on the assembly is loose and needs to be tightened. The gear is spinning but there is no tension to make the outdrives turn.
If all of that doesn't make sense, look in your manual and read the instructions on building your ball diffs. If you don't have a manual-- www.rc10.com--
go to the support section and download the manual in PDF.
Originally Posted by pool1027
Mr Hyde the wheels move fast when the car is off the ground but when it is on the ground it sounds like the motor is spinning fast but the car moving slow.