It is already one of the most whispered-about bits of legislative gamesmanship of the session, the curious and circuitous committee assignments of Senate Bill 85.

After being filibustered to death in the last session's waning moments, the bill to raise truck weight limits on Maryland's highways -- one of the most intensely lobbied measures of 1979 -- is back again. "This year," says one of its most dogged opponents, Sen. Howard A. Denis (R-Montgomery), "they're trying to rig the outcome."

Ordinarily, the Senate's Constitutional and Public Law Committee would get matters, like this one, dealing with motor vehicle laws. But the committee has a history of killing the measure. This year, Senate President James Clark Jr. (D-Montgomery), who calls himself a "new convert to the bill" because he believes it could conserve energy, took the unusual step of assigning it jointly to two committees -- one of which is expected to give it a friendlier hearing.

The bill's prospects for passage by the General Assembly this year are excellent, according to several legislators.

Denis charges that the joint assignment stacked the deck in favor of a bill that, could mean millions to the trucking industry. "What we're going through next week is going to be a charade," he said of the joint hearing scheduled today.

Clark asserts that the joint assignment to the Constitutional and Public Law and Budget and Taxation committees is "legitimate" because the truck weight bill contains a "tax measure," a change in truck registration fees.

But the committee routing that seems so curious to so many illustrates how the prerogative to assign bills in the General Assembly can vastly influence their fate. Rarely does a bill survive after a committee rejects it.

The controversial truck weights bill, which would increase the maximum weight allowable on state roads from about 73,000 to 80,000 pounds, has been pushed by the trucking industry as a gasoline conservation measure. But Bennett Whitlock Jr., president of the American Trucking Associations, conceded that it likely would mean a "monetary gain to the industry, and to consumers."

Opponents of the bill, including the Teamsters union and the American Automobile Association, argue that increased weights will damage roads and that heavier loads make driving unsafe. i

The arguments are reminiscent of last year's, and the intricate maneuverings surrounding SB 85 this session are also right in tune with its history.

Championed by the trucking industry, cherished by one of the legislature's most influential chairmen and pushed by the Hughes administration, the bill last year engendered a final-day filibuster that threatened to scuttle much of the assembly's work.

For a time, House Appropriations Chairman John R. Hargreaves, who owns stock in Maryland's largest trucking company, threatened to hold the state's $150 million capital budget hostage unless the bill were passed.

As the minutes before midnight adjournment began to run out, Gov. Harry Hughes, one of the bill's staunchest supporters, began calling legislators to his second-floor office, prompting one senator to derisively compare the governors' lobbying tactics to those of Hughes' predecessor, Marvin Mandel.

Finally, the truck weight supporters gave up, and the session moved to a dramatic close.

This year, the Maryland Motor Turcking Association already has thrown its lavish freebie banquet for legislators, plying them with clams casino, oysters Rockefeller and liquor. So concerned is the associaiton with the privacy of this gathering, that its lobbyist summarily dismissed reporters who tried to buy tickets to the event.

"They keep giving themselves this aura of sleaze, turning reporters away, making such a fuss," said Del. Timothy Maloney (D-Prince George's), who supports the truck weight bill. "If they just came in and made a solid presentation, they'd be better off."

Hughes supports the bill this year, as he did last session, pointing to the energy conservation argument. But some of Hughes' biggest campaign backers, including Preston Trucking, Black & Decker and Bethlehem Steel, also would profit from the bill that would increase their shipping loads.

Last year, when the bill came to the Senate, already approved by the House, Clark first assigned it to the Finance Committee. But members of Constitutional Law -- the bill's traditional home -- became so incensed, Clark changed it to a joint assignment. Finance, as was expected, gave the measure its blessing with a 7-to-0 vote. Constitutional Law voted 7-to-0 against it. The voting draw resulted in the bill coming to the Senate floor with no recommendation.

This month, when Finance Chairman Melvin A. Steinberg (D-Baltimore County) found the bill in his committee's calendar again, he promptly moved to get rid of it, writing a letter to Clark asking that the assignment be changed.

"I felt that our committee should not have been given the bill at all," he said last week. "Last year, we [the committee] prevented an unfavorable report and got the bill before the General Assembly for consideration I did it once, but I felt, I'm not going to do it again.

So up it popped, via Clark's guiding hand, in Sen. Laurance Levitan's Budget and Taxation Committee, much to the surprise of some of its members.

"I don't know what the heck it has to do with fiscal matters," said Sen. Francis X. Gelly (D-Baltimore County).

"I don't know why it's here," said Sen. Julian L. Lapides (D-Baltimore). "Ask Jim Clark. I'd like to hear his answer."

Said Clark: "I can understand people wanting to know why. But if I can defend what I do with logic, then it's fine."

Levitan, a Democrat from Montgomery County, has an answer, too. "Of course it's political," he said of the assignment. "But I didn't orchestrate it."

"Is that the way assignments should be made?" Levitan said, mulling over a reporter's question. "It depends on what you want. If I'm president of the Senate, and I want a bill out, I send it to a committee that will act on it favorably."

"I don't see anything wrong or devious about it," he added, noting that the bill does have a revenue measure attached to it.

Sen. Edward J. Mason, the Republican minority leader from Cumberland who supports the bill and sees nothing wrong with the committee routing, summed up the jockeying with this prediction for its future.

"It'll go to the joint committee. It will not pass Con-Law. It will pass Budget and Tax. It'll come out on the floor . . . and there'll be all sorts of debate and lots of chest-pounding.And then it will pass.

"Democracy in action," Mason added after a pause. "Enough to make you sick."