NEW YORK (Reuters) - GMAC LLC said on Wednesday it plans to cut 5,000 jobs at its Residential Capital LLC mortgage unit, or 60 percent of that work force, and shut its 200 GMAC Mortgage retail offices to combat persistently weak housing and credit markets.

GMAC also plans to stop offering home loans through its Homecomings broker channel, and is evaluating strategic alternatives for its GMAC Home Services and noncore mortgage servicing businesses. It said it keep offering mortgages "where there is a secondary market to sell the loans."

The cutbacks suggest deepening problems for GMAC's owners. A group led by private equity firm Cerberus Capital Management LP (CBS.UL) bought a 51 percent stake from General Motors Corp (GM.N) in 2006. The automaker owns the remaining 49 percent.

ResCap was the seventh-largest U.S. mortgage lender from January to June, making $35.7 billion of loans, according to the newsletter Inside Mortgage Finance. It said the latest job cuts will leave it with roughly 3,000 employees, down from a reported 14,000 at the beginning of 2007.

"While these actions are extremely difficult, they are necessary to position ResCap to withstand this challenging environment," ResCap Chief Executive Tom Marano said in a statement. "We need to respond aggressively by further reducing both operating costs and business risk."

GMAC is based in Detroit, and ResCap in Minneapolis.

ResCap has had seven straight unprofitable quarters, losing $7.2 billion over that time. In the April-June period, it lost $1.86 billion, while GMAC overall lost $2.48 billion.

ResCap expects 3,000 of the job cuts to take place this month, and a majority of the remainder by year end. It expects a $90 million to $120 million, and an additional charge for the other job cuts.