The Defense Department, in an apparent effort to improve its image, has recommended to the White House that Pentagon Inspector General Joseph H. Sherick be put in charge of buying and maintaining weapons, administration officials said yesterday.

Sherick recently recommended that Chairman David S. Lewis and two other top General Dynamics Corp. executives be suspended from participating in Navy contracts because "they lack business integrity and honesty," as demonstrated by submission of fraudulent bills to the government.

If the White House approves, Sherick would take over procurement and logistics under a reorganization plan opposed by Senate Armed Services Committee Chairman Barry Goldwater (R-Ariz.).

Goldwater has said he opposes it because it "may undermine the ability to manage the important and difficult readiness program of the Department of Defense."

Under the plan designed by Defense Secretary Caspar W. Weinberger and Deputy Defense Secretary William Howard Taft IV, Sherick would become an assistant defense secretary. He would assume logistics functions now handled by the manpower chief and acquire weapons responsibility from the undersecretary for research and engineering.

Weinberger announced the plan in January but has not named anyone to fill the new post. By transferring Sherick, Pentagon officials said, Weinberger would gain in the sense of projecting an image of cracking down on contractors but lose what he gained in having a reputed "tough guy" as inspector general.

In a letter to Weinberger challenging the reorganization plan, Goldwater said "the substantial benefits of having one assistant secretary integrate the major readiness functions would appear to be lost" by splitting manpower, logistics and acquisition.

House Armed Services Committee Chairman Les Aspin (D-Wis.) has also expressed reservations about the plan.

Given the political backlash on the Senate panel about the Pentagon's sudden disclosure this week that it had discovered $4 billion that could be added to the fiscal 1986 budget, the White House may decide to keep Sherick's proposed switch on hold rather than cross Goldwater.

Goldwater on Thursday said Weinberger lost credibility with Congress by waiting until just before the Armed Services Committee markup of the fiscal 1986 defense authorization bill to disclose the extra money. "The goddam fool should have sent it the notification up four months ago," Goldwater said.