How far and fast is change in the Soviet Union likely to go? After five-year absence, reporter glimpses newness amid much that is the same. MOSCOW REVISITED

Wednesday: The plane from Frankfurt lands in the gloom and soft dusty snow of late afternoon. Somewhere out there, beyond the runway lights, lurks something that the Russian Slav has feared throughout his history: change. The whole world wants to know how much, how fast, for how long.

I was last here five years and three leaders ago. What clues, what change will I find?

At first, it all seems the same. Sheremetyevo Airport is still glass-sided modern on the outside, KGB and bureaucratic on the inside. Heading for the Intourist car to the hotel, the same slush reaches for the ankles, the same pungent low-octane gas fumes stream from exhausts.

The same winter darkness, the same wide thoroughfares, lined by the same endless, uniform, domino-like apartment houses. The minimal lighting is still a shock after the West. There's more traffic than before, but still far less than in Western capitals.

The old familiar lack of color: no bright lights in store windows, few neon signs, dark clothes, pedestrians dwarfed by concrete-cliff buildings and the gaping width of main streets.

To the Hotel Belgrade. Am assigned a wing no foreigners stayed in until recently. Hotel shortage is the same, exacerbated by a flood of businessmen and journalists wanting to know about Mikhail Gorbachev's reforms. Famous old Metropol Hotel near Red Square closed (being refurbished by the Finns.) When official guests take precedence at major events (such as the recent Nov. 7 parade), businessmen must stay away, and visiting journalists must sleep on couches of resident colleagues.

My room is about nine feet square. No shower curtain, but water is hot. Manage to avoid (mostly) three nails sticking up on threshold of the bathroom. View across Moscow River is dark buildings, dark sky.

Downstairs in coffee bar, two women behind counter smilingly serve me, even though they are about to close. I sense again the warmth of the people, enduring hardships by wrapping themselves in shared experience.

As usual, hotel has no switchboard. Each room has a separate city number. No official citywide phone book. Foreign community has own mini-compilation of numbers, so know I can book an overseas call by dialing 333-4101.

Thursday: More sameness: breakfast in cavernous, dingy hotel restaurant is thin cheese, thin salami, bread, luke-warm tea.

The drive to the apartment block in which my family and I lived for almost five years is exactly the same: same underpasses, same slush-spattered traffic, ancient trucks, gray-coated militia-men controlling the traffic, unpainted, monochromatic, concrete world.

Building is reserved for foreigners, so same uniformed guard in same windowed sentry-box checks everyone. Joyful reunion with maid and car-driver employed by this paper for many years. Same clutter of reference books, Tass wire-service rolls in office. Same immersion of foreign correspondents in the mysteries of Moscow and the Kremlin. Only new note: computer screens instead of typewriters.

Evidence of change emerges at dinner with US Ambassador Jack Matlock and wife - both personal (almost all Soviet staff let go since Marine guard spying episode, so Rebecca cooks meal, and Jack drives himself to the Embassy) and professional (Matlock recently spoke on US perceptions of the Soviet Union to 280 senior officers in the Soviet West Point, the Frunze Military Academy. Change indeed.).

Embassy thinks glasnost (openness) and perestroika (restructuring) are opportunity for West in general and US in particular. Effort to decentralize economy will disperse - to a degree, anyway - decisionmaking. A kind of political process could emerge. Gorbachev said to be distracted from more Angolas or Afghanistans. Soviets seen as less likely to risk confrontations meaning more guns, less butter.

If reforms fail, Soviet Union will be poorer but not necessarily more aggressive abroad, the theory holds. Fact is, no one really knows. It's generally agreed, though, that Gorbachev's efforts are extremely important, well overdue, and historic in scope and implications.

Russians and Westerners alike ask, what about prices?

They're rising in Eastern Europe, causing panic buying and concern about new rebellion in the streets. As usual, Moscow is the last to move. Factories accounting for 60 percent of output begin ``self-financing'' - planning own production schedules, output, and staffing - Jan. 1. Yet prices are to stay the same for now, changing only in two or three years. No one knows just how or by how much. Sameness in the midst of change: We just don't know. Maybe the Kremlin doesn't know yet, either.

The new freedom of expression remains limited, controlled. The recent news about the sacking of Boris Yeltsin was given to foreign correspondents several times before his firing was announced in Pravda. What he actually said to earn dismissal still hasn't been revealed. Colleagues say pro-reform Soviet friends were dismayed: Are the changes now slowed, even derailed? Again, no one knows for sure.

I pick up a copy of Moscow News, a weekly. It interviews a Russian journalist who emigrated in 1979 and was allowed back in for an Ottawa newspaper. (Once such a return was unthinkable.) He says he has been better able to work as a journalist in the West. He praises glasnost: ``Never ... have I seen such a landslide of hopes.''

Change: US diplomats live in rows of new apartments and town houses on new US Embassy grounds, after a decade of construction. Offices still empty because of US concern about Soviet bugging. Building may never be occupied. Five top stories to be rebuilt. Dine with old friends, journalists. Am shown new cafeteria, new swimming pool, new basketball court.

Sunday: Lunch with BBC-TV's Brian Hanrahan at new Mezhdunarodnaya Hotel (known to foreign community simply as ``the Mezh''). Unprepossessing concrete exterior. Huge Hyatt-syle open lobby, glass-sided elevators, fountains, trees, crimson carpets, chromium-plated lights: Moscow's answer to Western luxury hotel.

After many months here, Hanrahan is still permitted no office. He shares cramped rooms with Jeremy Harris of BBC radio, who broadcasts to 100 million listeners a week in Britain and on shortwave World Service from little more than a shoebox.

Long line at liquor shop: Gorbachev's strictures against drinking have closed many. Everyone buys same: three small bottles of vodka. Many more people make home brew: sugar consumption shot up 14 percent last year. Fewer drunks on street, but more appearing now.

Monday: More change: walk the length of the Arbat, famous old Moscow street. Now a pedestrian mall. French-style street lights: clear globes on black metal stands. Some new shops. Hard to be fashionable and insouciant in thick overcoats and cheap fur hats. Nice try, though, and must be pleasant in summer.

Walk down hill and turn left on Karl Marx Prospekt. The yellow-painted Manege exhibition hall, formerly Czars' stables, now closed to store books from the Lenin Library (also closed, for repairs.) Main Conservatoire concert hall closed. Famed Bolshoi Opera and Ballet House supposed to be closed for repairs lasting years, but is still open. Repairs said to be scaled back.

And some things never change: catch glimpse of the striped onion domes of St Basil's Cathedral at far end of Red Square. Spectacular splashes of color against the gray. Will glasnost/perestroika be just that? Or will the grayness win?

Mr. Willis was the Monitor's Moscow correspondent from 1976 to 1981. He is the author of the book ``Klass: how Russians really live.''