Brrr

I just bought a JD 928E at Lowes. The only complaint the I have is that, intermittently, the drive slips in any gear as soon as any real load is put on it. It is a pain to drag or push it to get it going again. Is this is going to be ongoing problem?  If so, I think I will return it. (Otherwise, it is great - thing can really throw some snow; also, the B&S starts first pull everytime and runs flawlessly.)