THE APPOINTMENT of Teamster Vice President Jack Presser as a senior adviser to President-elect Reagan's economic affairs transition team raises some troubling questions. While Mr. Presser can, no doubt, provide the new administration with advice on labor-related matters, it is far from clear that it is the kind of advice Mr. Reagan ought to be soliciting or, for that matter, receiving.

In his new role, for instance, Mr. Presser may well be in position to have some influence over who is appointed to the Labor Department's top jobs and what policy lines they initially pursue. That puts him in a curious situation, since he is also a defendant in a lawsuit filed by the Labor Department charging that he and some others mismanaged Teamster pension funds. The prospective conflict here is obvious. No one charged with this kind of wrongdoing ought to be in a position to have any influence with the officials who will be responsible for handling the case in the future.

But there is something more. There have been links between the Teamsters and the mob in the not-too-distant past. One of the pension funds of which Mr. Presser was a trustee in the mid-1970s had previously made vast sums of money available to men who can be described at best as unsavory. The Labor Department's lawsuit suggests the fund never substantially changed its policies. That's one of the reasons questions arose immediately after his appointment about his personal relationships with mobsters.

During the campaign, the Teamsters did support Mr. Reagan, and Mr. Presser's appointment may be no more than just a meaningless, pro forma reward for services rendered. But appointing a man with Mr. Presser's strange credentials to this job is simply buying trouble -- it's a kind of down payment the president-elect is going to regret.