What do you mean "bleeding off"? Electric winches on 4-wheelers and SxS's don't have any type of brake, it is all planetary gearing. Is the cable dropping down through the underlying wraps of cable? If that is the case then the winch cable needs to be wound onto the drum tighter. If the weight of the plow is too heavy for the winch, it may override the gearing and motor and pull the cable out, never have I seen this happen.