It's impossible to know exactly how much any one action will alter one's FICO score with any one CRA.
If you need to get a new car loan, then you need it. Period. Whether the tranny blew, got stolen, wrecked or whatever, you need it, right?
Did your new car loan replace an existing car loan? If there was some circumstance--stolen, wrecked, etc.--then any sort of documentation you provide the loan officer would help assuage their concerns, assuming they have any, and it's possible they won't care.
Check out the Credit Monitoring link in my sig. Might be a good time for you to sign up for MyFico ScoreWatch on a month to month basis. First do a google search and find a current Myfico discount code before you buy. Keeping an eye on your EQ FICO score for a couple of months might prove useful for the home refi.
