While raising the tax on gasoline, the Reagan administration would eliminate the excise tax on automobile and small truck tires as part of its new highway tax and repair program. But for larger trucks it would substantially increase the tire and some other taxes, according to copies of the bill that trickled out yesterday.

The main provision of the bill is the increase in the existing federal gasoline and diesel fuel tax from 4 to 9 cents a gallon. This would all be collected at the refinery, as the gasoline tax is now; refiners would choose how much of it to pass along.

The gasoline tax increase would be paid by everyone. But lesser provisions of the bill would be more selective. Confirming the worst fears of the trucking lobby, these provisions would strike a heavy tax blow at the biggest trucks.

The idea is to make such trucks pay their fair share for the damage they do the nation's crumbling roadbeds. A recent Transportation Department study, which the truckers dispute, says they vastly underpay for this.

In return for the tax increase, however, the truckers would get something they want badly: the unfettered right to run heavier, wider trucks with as many as two trailers on any 12-foot-wide highway lane in the country. Truck width, weight and trailer limits vary from state to state and truckers have persuaded the administration that the lack of conformity results in a substantial loss of productivity.

The administration proposal would also:

* Ease environmental review requirements when a federally aided highway project would require the taking of parkland or land involving historical sites.

* Emphasize the early completion of the few unfinished -- and in most cases highly controversial -- sections of the interstate highway system.

* Substantially increase federal money for rebuilding tired bridges.

* Establish for the first time a "transit infrastructure" program to rebuild bus and subway systems.

* Eliminate by the end of fiscal 1984 all federal assistance for local transit operating costs, such as driver salaries.

All of these programs would be financed from the Highway Trust Fund, meaning the fuel, tire and some lesser taxes. The administration would adjust these taxes as follows:

* The existing 9.75-cents-per-pound tax on all tires would be increased to 25 cents per pound but levied only against tires weighing more than 100 pounds, thus eliminating taxes on tires for automobiles and many small trucks.

* The tax on retread rubber -- used mostly by truckers -- would jump from 5 cents to 25 cents a pound.

* An 8 percent tax on all truck parts would be increased to 12 percent but would be assessed only against trucks weighing 33,000 pounds or more; that would eliminate taxes on about 90 percent of all truck parts.

* The tax on new trucks is presently 10 percent of the purchase price on all trucks above 10,000 pounds. The administration bill would increase that to 12 percent and apply it only to trucks weighing 33,000 pounds or more, and thus eliminate the federal tax on about three-fourths of new truck sales.

* The existing heavy vehicle use tax of $3 per 1,000 pounds of gross weight for any truck of 26,000 pounds or more would be assessed only against trucks weighing 55,000 pounds or more and would be charged on an escalating scale.

* Existing taxes on inner tubes and lubricating oil would be eliminated.

The truckers have calculated that the package could increase fees on the heaviest trucks from about $1,600 annually to more than $5,000 annually, and "we're not accepting that," a trucking industry official said.