As Truck Robinson cruises around the NBA this season, loading up on rebounds wherever he stops, people keep asking him the same troublesome question.

"They will come up to me," Robinson said, and say, "Truck, look what you're doing now, doing this and that every night. Why didn't you do that in Washington?"

'And I tell them. "They didn't allow me to do it. Now I'm free at last, i can do what I want.'"

What Robinson is free to do is rebound, which he has mastered so well that his 16-a-game average is the NBA's best. Only once in the last 20 years has a nincenter won the rebounding title (Eelvin Hayes in 1974), but Robinson is convinced he can be the second, "because I'm in a situation where I can play up to my ability every night, which means I can do a lot of rebounding."

Yet Robinson remains convinced that he didn't need four years and a change of uniforms from Washington to Atlanta to the New Orleans Jazz to show he was this good. He could have done the same things for the Bullets, he says, if only given he same atmosphere in which Bobby Dandridge is playing in this year.

"The Bullets didn't have to go out and get Dandridge." Robinson said yesterday on the eye of his first appearance in Capital Centre (8 p.m., WTOP-1500) since joining the Jazz. "They had me and I was good enough to make them as good as they are now.

"Look at the frontcourt we could have had: Unseld, Hayes and Robinson. That would have been the best in basketball. But they never were willing to give me the freedom they gave the other superstars.

"Now Elvin isn't the dominant force he's been in the past. He's surprised me; I didn't think he could change. Now he'll make sacrifices and take only 10 shots a game if that's what they need to win. And they are winning, because I really think Elvin wants to win more than anything else now in his career.

"What puzzles me is that why didn't Elvin accept his current role when I was playing with the team? If he had, we would have been something.

"Bobby Dandridge might be having a good year, but he's not rebounding as well, he's not setting the picks I set for Phil (Chenier), he's no faster than me, he doesn't play the defense I play.

"They didn't need to go out and get him. They had me, I just wish it all ccould have been different. It didn't have to work out this way."

But it has worked out this way, with Dandrige as Washington's small forward and Robinson as New Orleans' big forward, because the Bullets were convinced Robinson was not what they needed in their championship quest.

That decision has made him a rich man (his contract from New Orleans call for $1.5 million over the next five years) with something to prove.

"It looked like when they traded me to Atlanta last year," said Robinson, "that they were blaming me for the team losing like it was. i had to prove that I was a player and that it wasn't my fault. I was think I've shown that."

But Bullet general manager Bob Ferry, who picked Robinson on the second round of the 1974 draft, says that despite his glowing statistics (which also include 22.5 points a game). Robinson's departure wasn't a management mistake.

"Truck is a big forward and he was playing small forward here," said Ferry. "We had Elvin and Mitch (Kupchak) and Truck and we couldn't have that many big forwards.

"Truck was also going to be a free agent at the end of the season, and I didn't think we had much of a chance to sign him. We were losing and I though the best thing we could do was trade for what we needed (playmaker Tom Henderson) and get something in value for Truck before we lost him completely."

I love Truck. He's my tennis partner in the summer and he is a supertalent. But you just can't toss three rebounding forwards and two guards on the floor and win. A team needs chemistry and we didn't have it last year.

"You can have too many rebouners, and we did. They were hurting each other."

Robinson, who admits Washington probably would never have matched his current contract, is just as certain that he is more adept at playing small forward, and he can't figure out why the Bullets could never see it that way.

"I feel I'm a small forward playing big forward," he said. "At 6-7, I'm small, but because of my weight (240). I'M strong enough to go against 6-9 guys every night.

"But it's not that much fun facing guys taller than you all the time. it's tough out there, you get pushed a lot and you're sore after games."

When Robinson left Washington, he was bitter about how he was treated and the way Hayes dominated the maneuver. But now he say the bad team, not leaving room for him to feelings between the two have disappeared and tonight's game has no special significance.

"That's over with now," he said. "Elvin and I have to go against each other a lot from now on and it's become just another game.

"People say I play him more physically than I do other people, but I have to, I have to push him or I couldn't stop him.

"He's 6-9 and 235. If I let him bully me and get into the spots he wants to go he'll score at will,I can't let that happen. At 6-7, I have to play him rough and tough and make him do what a I want."

When the two went head to head lastmonth in New Orleans, the duel was a standoff. Robinson had 21 points and 24 rebounds and Hayes contributed 21 points and 14 rebounds to Washington's 108-97 victory.

That was one of six games i n which Robinson has had 20 or more rebounds, including two of 27, a team record. He has put together some truly awesome performances this season, including 87 points and 25 rebounds against Phoenix, 32 points and 21 rebounds against Philadelphia 24 points and 27 rebounds against Indiana and 21 points and 27 rebounds against Los Angeles.

"Why am I doing so well?" he said, repeating a question. "I'm getting a lot of minutes (44 a game, tops in the league), which I never had before. And I'm a lot more experienced and I enjoy rebounding.

"When I came out of college (Tennessee State). I figured I could get 18 points and maybe 10 rebounds a game, I'm doing better now because I've always seen a rebounder and I work at it. Most of the big forwards were scorers in college, they didn't do much rebounding. It's new to them, but not to me."

Robinson says he feels he owns a triangle-shaped area around the basket. "It's like a funnel," he said. "Anything in that funnel, I'm not willing to give up very easily.

"You've got to concentrate, to make sure those 6-9 guys don't get in front of you. Scoring is easy, rebounding isn't. And it's getting harder. Teams are assigning guys to me now who just worry about keeping me off the boards. They don't even care if they shoot.

"I've had to study my men more, I don't have that great instict for the ball like Moses Malone or I'd have 20 (rebounds) a game. I've got to be smart and use my strength, especially in my forearms, to be this consistent."

Robinson already has become the best forward in Jazz history and has proven pete Maravich, the league's top scorer, a prophet as well. maravich told the Jazz to sign Robinson so the team would have a good rebounder and then he would agree to a new contract, which he didn't for five yers and $2.5 million.

"This team isn't built around me, it's built areound Pete," said Robinson. "But I'm not complaining. this is what I've always wanted in the pros; freedom to be myself. It sure makes life more enjoyable.?

New Orleans has lost its last five games, including three on its current road trip . . . Coach Elgin Baylor may shake up his lineup tonight; new starters could be Joe Meriweathe at center (in place of Rich Kelley), Gail Goodrich at guard (in place of Fred Boyd) and Paul Griffin at forward in place of Aaron James).