If grant deed has no trustee then can lender force sale?

The security instrument usually used to secure a home loan is a Deed of Trust. From your description, it sounds like what you and the seller have is a Land Contract. Under this arrangement, the seller holds the Grant Deed until the loan is paid. Did you and the seller sign a written contract? If so, you need to read it carefully to see if it includes a forfeiture clause. This is the part of the contract that states the procedure the seller must follow to retake possession of the property in the event of default. If your agreement was oral (not in writing), then it is probably invalid and unenforceable because of the Statute of Frauds, which requires all contracts concerning interests in real property to be in writing. But even if the contract is unenforceable, the seller can probably file a lawsuit to get the property back. In that event, the court could require him to refund all of the payments you have made. You really need to speak to a lawyer right away.

A grantee without a trustee does not invalidate a potential trustee's sale.