look over the 2021 return to make sure you didn't take 100% of the cost as depreciation in 2021. that's what Turbotax is indicating by reporting the proceeds as the gain. we can't see your returns and 6600 looks low unless there was substantial personal use. look at form 4562 for 2021.
depreciation recapture is not capital gain but ordinary income that would show up on form 4797. only $5000 would be capital gain but the van would have had to been held for over 1 year.
