Credit Karma scores are useless for auto loans. Don't believe those scores at all. You have a seperate auto score for each agency and those are the scores the banks and credit unions use (with very rare exception). I suggest (strongly) applying for financing with a credit union like DCU, Penfed or NFCU before you do anything with a dealership. The dealer will blast your applications to many banks and they will run whatever credit scores they use and the dealer will often mark up the interest for the "service" they have provided you. Walking in with a preapproved loan and check in your hand makes the transaction much easier.
I wouldn't weed out lenders until you knew your actual auto FICO scores, you will have to pay to learn them or apply and get them from the lender. I think its well worth a few bucks to know them if your shopping for financing of a car or house.
The reason I say Credit Karma scores are worthless is they say my Equifax is 587 but my actual Equifax is 673, they say my Transunion is 608 and its really 667. I have had times where CK says my scores are higher then they really are also. Of course my auto scores are totally different than my fico 8 so these scores can be misleading and can lead one to believe they have a good score with one agency when they really don't. Most of the time the scores will be fairly consistant accross the agencies unless you have a collection that was reported to one agency and not the others for example.