In 2010, we purchased a tractor and added a trimble auto pilot system to it. The tractor was recorded as equipment purchase and the auto pilot system as a depreciable improvement. The tractor was traded in 2015 for a new tractor. The new tractor was recorded as equipment purchase with the old tractor as a trade in. The auto pilot system was kept and moved to the new tractor. I just noticed the traded transaction caused the auto pilot system to be removed from the equipment account and accumulated depreciation account. Since we kept the auto pilot system, how should I go about getting the it back on the books?