TV Corp., whose controversial bid to buy Grumman Corp. was halted, at least temporarily, by a federal judge, said today that it would extend its offer to by Grumman stock from Friday until Nov. 3.

LTV has appealed a ruling by Judge Jacob Mishler that barred the Dallas-based conglomerate from going through with its $450 million bid for the Long Island aerospace company. Mishler said he found reason to believe such a merger would violate the nation's antitrust laws.

Hearings on the LTV appeal are scheduled for Oct. 28. The antitrust suit was filed by Grumman, which has been fighting off the LTV bid. Mishler prohibited LTV from either buying or soliciting LTV stock until he held hearings on the antitrust charges.

Earlier this week, the Labor Department filed suit against trustees of the Grumman pension plan for using pension fund assets to buy Grumman stock. The Labor Department asked that the three trustees of the plan, one of whom is Grumman chairman John Bierwirth, be replaced. The plan, which now owns about 1.7 million shares of Grumman stock, bought 1.2 million of those shares last week.

The pension plan buying was part of Grumman's overall strategy to fend off LTV. The pension plan--as well as the employe investment plan and the company itself--bought the stock to keep it from falling into LTV's hands. The pension fund bought the stock at about $37 a share. LTV's offer is at $45 a share. After Mishler's antitrust ruling, however, the professional traders who bought Grumman stock in hopes of selling to LTV at a profit started to sell that stock. That drove Grumman's price down to $29 or less.

On paper, the pension fund has lost more than $11 million on its purchase of 1.2 million shares of Grumman stock.

Mishler has scheduled hearings on the Labor Department suit for Oct. 30.