Grumman Aerospace Corp. announced plans yesterday to cut the price of aircraft ashtrays sold to the Navy from $660 to $50 each and to refund the difference.

The decision came a day after the Navy admitted paying the higher price and after the Pentagon, saying there is "no excuse" for such a high price, demanded an "immediate" repayment from Grumman.

Joseph Vranich, a Grumman spokesman, said the company thinks that its original price was "in order," given the production costs of each ashtray for the E2C electronic surveillance aircraft. Each ashtray, a 4-by-4-inch receptacle that fits into the plane, takes 11 detailed parts and 13 hours of labor to manufacture, he said.

Seven ashtrays had been ordered by the Navy, he said, and Grumman will refund $4,270.

Grumman defended its prices of $400 each for socket wrenches used to adjust ejection seats of the F14 fighter plane and $2,710 each for landing-gear clamps -- prices Vranich said are justified by the labor involved in making them.

He was unable to explain, however, why the price of the clamp increased more than 2,500 percent over a 16-month period. Vranich said Grumman will suggest that the Navy find another supplier for all three spare parts if it is unhappy with the company's pricing.