According to the 1985 Moss Magnuson Act, warranty and guarantee are the same thing.
A guarantee is a document to protect consumer rights. It is a promise by a seller with a buyer for complete replacement of the item/ article or product; usually guarantee is valid for a fixed period of time. It has a legal status, even if we do not pay for or it was offered free of cost by a seller.
Warranty is also a document that protects consumer rights. It is more or less like insurance policy for that we have to pay certain amount to come into legal contract. So on the basis of this legal bond the company can be taken to court if it does not bound what has been agreed in the warranty document. Warranty covers only repair of the article.
Guarantee is more in manufacture, Warranty is more in distribution and reselling parts; for example, a company manufacture a scooter is liable for manufacture guarantee,on the other hand, some importer or distributor resell the products will use warranty
http://www.edroman.com/general/changes.htm
Perhaps the biggest difference that I've observed in practice (and it is a small difference) is that "guarantees" sometimes use buyer satisfaction as the criterion to determine whether or not a remedy is due to the buyer. As in "satisfaction guaranteed or your money back."
In contrast, for a remedy to be due to the buyer under a warranty, there usually is other objective criteria such as durability for a certain period of time or conformance to specifications. There are also specific warranties that may apply under the law.