Senate investigators have been told of evidence that some of the money from a secret bank account here in the name of Sen. Herman E. Talmadge (D-Ga.) was used by a former Talmadge aide to pay for repairs on the Georgia senator's car.

Talmadge, under investigation by the Senate Select Committee on Ethics, the Internal Revenue Service and a federal grand jury here, acknowledged last Friday that his name appeared on a secret account of nearly $40,000 that was active in the Riggs National Bank in 1973 and 1974.

But the Georgia senator emphatically denied any knowledge of the bank account until he was told by his staff two weeks ago.

Talmadge has indicated the former aide, Daniel Minchew, was responsible for the account. Minchew, who operated the account, said he did it on Talmadge's orders.

Sources close to the investigation of Talmadge said yesterday that an attorney for the former Talmadge aide had told Senate investigators Minchew has receipts that will show some of the money from the secret bank account went for reparis on Talmadge's car.

Talmadge has said that, with the exception of one $300 check that he wrote for his personal account in the bank. In all, the sources saon small cash gifts he received from friends and supporters.

Minchew's attorney, Robert G. Fierer, declined yesterday to comment on any evidence he has linking the Georgia senator to the hidden account.

Minchew, who left Talmadge's staff in 1974, is a member of the International Trade Commission.He is scheduled to testify to the Senate committee after Sept. 20. Committee officials will go into federal court here Friday to ask for limited immunity for Minchew.

Sources familiar with the bank account said yesterday that between $5,000 and $6,000 of the nearly $40,000 in the Riggs account was transferred by Minchew to his personal account in the bank. In aa, the sources said nearly 40 checks were written on the account, each one to cash and each one signed with Talmadge's automatic pen signature machine.

The account, which has been dormant since last 1974, still contains about $113, the sources said.

Both the Justice Department and the Senate Ethics Committee have subpoenaed the Riggs accounts of Minchew ad his wife, Shirley.

According to the sources the investigators looking into the account have had difficulty tracing the source of the checks deposited in the bank. Riggs routinely destroys copies of deposited checks after two years.

Senate investigators have had to settle for copies of the account's deposit slips. None of the slips contains a name, sources said, and only about six have legible bank routing numbers to indicate which banks the check deposits to the account were drawn on.

According to sources, nearly $13,000 that went into the bank account came from Senate reimbursements that were improperly claimed. The rest of the money, the sources said, came from Talmadge campaign funds. They said it was not clear whether all the campaign money was properly reported in federal election reports.