J.Crew’s legendary chairman and chief executive Mickey Drexler is asking for help to turn around his ailing chain, The Post has learned.

Drexler, who is credited with the Gap’s success in the ’90s, has been working with consultant McKinsey & Co. on developing a new business plan for the preppy J.Crew retail chain, two sources with direct knowledge of the situation said.

Private equity firms TPG Capital and Leonard Green & Partners, with Drexler, own J.Crew and the dynamics of the partnership are changing.

“I think there was a lot of deference to Drexler and that is now over,” a source said.

Meanwhile, to give it more time and latitude to fashion a revival, the retailer may soon hire a bank to explore the idea of buying back its bonds — currently trading at 38 cents, a source said.

J.Crew has a little over $2 billion in debt: a $1.5 billion loan maturing in 2021 and $500 million in bonds maturing in 2019.

The company has basically no free cash flow, according to a Barclays analyst report. However, as of July 31, it had an untapped $320 million credit line and $49 million in cash.

If it buys all its bonds for its market price of $209 million, there will be no maturities for five years, giving Drexler and crew time to make the brand fashionable again.

“The perception of the chain in the eyes of the customer has been compromised,” one of the sources said. “J.Crew realizes it needs to get more comfortable clothes and be more like Lululemon.”

Among the changes on the table:

A greater emphasis on activewear and less on tailored clothing. Last week, J.Crew announced its first activewear line in partnership with New Balance.

Being able to replenish popular items quicker. J.Crew is weighing the formation of a team to address faster production times, one source said.

Possible greater focus on online sales that could result in the closing of some stores, the source said.

TPG has had two very different experiences with Drexler, 72, a Bronx High School of Science alum.

David Bonderman’s firm in 2003 recruited Drexler to run J.Crew amid much fanfare. The move helped TPG’s fund turn its $133 million 1997 J.Crew investment into $930 million by the time it fully exited in 2009, TPG’s fund documents show.

In 2010, J.Crew’s performance fell and TPG a year later made a contrarian investment in partnership with Drexler, buying the then-listed company for the second time.

However, TPG’s much larger $650 million fund investment has returned only $357 million in fees and dividends, according to fund documents.

The fund’s stake in J.Crew is worth very little considering the company’s bonds are trading at distressed levels. Debt typically gets paid before equity. Combined, TPG funds over almost 20 years have invested $783 million in J.Crew and realized $1.26 billion, according to fund documents.

Both TPG and J.Crew declined to comment.