The Miami Dolphins team that goes against Washington Friday night at RFK Stadium will be very different, in spirit and makeup, from the one that played the Redskins in Super Bowl XVII.

Before they had faced a single opponent this preseason, the Dolphins lost two of their most valuable defensive players. Larry Gordon, the outside linebacker, died of a heart attack June 25 as he jogged in the desert outside Phoenix. Don McNeal, the cornerback who was Miami's best pass defender, ruptured an Achilles' tendon in an intrasquad scrimmage the week before the team's exhibition opener.

And nothing has been the same since. Gordon was one of the keys to the pass defense that was the best in the NFL last season. McNeal led the team with four interceptions. Already faced with bolstering a run defense that ranked last in the league in average yards yielded, Miami's defensive problems were exacerbated by the double loss.

"It's a disturbing thing when you have this many questions at this stage of the preseason," Dolphins Coach Don Shula said. "At a time when we should be improving as a defense, we're just trying to find out who can line up and play. We're having some problems we didn't anticipate. We need to find things out in a hurry."

Toward that end, the Dolphins traded an undisclosed 1985 draft pick to the Denver Broncos for veteran linebacker Larry Evans. Also precipitating the trade were injuries to promising second-year players Charles Bowser and Ron Hester, who were competing for Gordon's position. Bowser's injury, a pinched nerve in his neck, appears to be improving, but Hester will be out eight weeks with a knee injury.

Still, Miami's prospects are not quite as bleak as they may appear. Offensively, the team should be improved. Quarterback David Woodley has not been haunted by the memory of his zero-for-eight passing performance in the second half of the Super Bowl. He has been a much more confident, commanding presence in the huddle this summer, and two strong performances in exhibition losses to Dallas and New Orleans have fed his new, self-assured demeanor.

Although rookie quarterback Dan Marino has impressed Shula with his awareness and ability, there will be no quarterback controversy in Miami this season. Don Strock, the other half of the "Woodstrock" quarterback combo of 1982, has not come to terms with the team and is leaning toward signing with the Memphis Showboats of the United States Football League. Shula has given third-year man Jim Jensen plenty of work.

Fullback Andra Franklin, who carried the bulk of the Dolphin offense on his back last season, will not be overused this year. David Overstreet, the club's No. 1 pick in 1981, has returned after two undistinguished seasons in the Canadian Football League, and his presence has served to spur Tony Nathan.

Veteran wide receivers Duriel Harris, Jimmy Cefalo and Nat Moore are being pushed by second-year man Mark Duper and rookie Mark Clayton. Running back Tommy Vigorito also is competing for a wide receiver spot.

The draft acquisition that probably has had the most immediate impact has been that of punter Reggie Roby, a sixth-round pick from Iowa. Roby led the nation his junior and senior years, and judging from his two exhibition performances he might be a threat to lead the NFL this season. His average for six kicks has been 54 yards.

Balancing defensive questions against offensive promise, Shula comes up with a mixed prognosis: "There are a number of things we still have to find out about this football team," Shula said. "We've seen a lot of good things so far--Woodley's performances, Roby's punting, the play of some of the young guys in the secondary--but we have some unsettling questions to answer, and we have to answer them soon."