The average new-vehicle monthly finance payment reached $821 in September, up 3% year-over-year and a record for the month, according to a joint forecast by JD Power and GlobalData.

"A key driver of the higher monthly payment, despite longer loan terms, is lower trade-in equity,” said JD Power President of OEM Ssolutions Thomas King.

“Many buyers returning to showrooms today purchased when prices were at their peak several years ago, when inventory was scarce.”

Twenty-nine percent of car buyers had trade-ins with negative equity, and in an effort to manage monthly payments 14% of loans had terms 84 months or longer, a two percentage point increase year-over-year.

Some relief was found as the average new-vehicle loan interest rate dropped four basis points to about 6.7%, but JD Power pointed out that wasn’t enough to offset the aforementioned persistent affordability challenges.

The average retail transaction price was flat at $45,915.

Total new-vehicle retail sales for September were projected to be flat at 1.1 million units with a seasonally adjusted annual rate of 13.9 million units, also flat compared to last year.

For the third quarter, sales were projected to reach about 3.5 million units, down 2% year-over-year on the same number of selling days.

As for powertrain mix, internal combustion engine sales rose nearly 4%, holding the majority share at nearly 74%. But hybrids continued to gain popularity, taking 17% of market share, up 3.5% year-over-year.

Electric-vehicle share dropped 6.5%, but the year-over-year comparison is skewed as buyers rushed to purchase last year before the end of the federal EV tax credit.