the standard mileage rate IS NOT entirely depreciation it covers operating costs like gas, oil and insurance
the actual depreciation (regular and AMT) you took based on IRS pub 463 page 24 is 26 cents per mile ($5996 if my math is correct) which must be manually entered. Turbotax does not calculate depreciation when the standard mileage rate is used. THERE IS A BUG in Turbotax since the beginning and ending mileage are the same Turbotax computes 0% business use. Then it completely ignores the cost and depreciation entered (MODS). the way around this is to enter ending mileage 1 mile higher. then it computes 100% business use and correctly calculates the gain
assuming my math is correct
71208-5996= 65212 = basis
sales price 68000
gain 2788
not sure why you took standard mileage in 2021 since 179 depreciation and/or special depreciation would have allowed a greater deduction (minimum over $18,000 depending on the class of the truck). in addition, you could have deducted other expenses like gas, oil and insurance. but then you would have had a bigger gain in 2022
