Dispose of asset

Two person LLC - sold a truck which had a section 179 deduction and was fully depreciated. I answered the questions and  input the sale of the truck. TT has entered a code L in box 20 on the K1 which only accounts for the section 179 deduction. There is a 20,000 gain on the sale of the vehicle. I read that if a Section 179 was allowed on an asset the sale does not carry to form 4797 (for llc -partnership) but the information is provided on  Schedule K-1 Box 20.  There is no form 4797 which I guess is correct but I don't know how to input the sale amount in the K-1.