I'm not sure what the relevance of this monthly amount is.
The fact is, you've derived very little utility & usage from your current vehicle.
Since you drive so little, the current car will last a lifetime (will take 50 years to reach just 120K miles).
So spending $3900 to get the same vehicle, but with 2400 fewer miles, provides virtually no value.
The new car isn't going to last you longer, isn't going to cost less in maintenance/repairs, isn't going to provide meaningful resale 10 years down the road.