DETROIT—With his company burning through cash and auto sales sinking to historic lows, GM’s CEO Rick Wagoner is pushing hard for a merger with Chrysler, and lenders are lining up in support of the deal.

The merger discussions are gaining momentum as both sides want to reach an agreement within the next two to three weeks. Financial institutions that hold Chrysler debt, including JPMorgan Chase and Goldman Sachs, are pressing Cerberus Capital Management, which owns Chrysler, to sell the automaker. MORE