What is the cost to repair a leaking front differential? on 2004 Toyota Sienna

I have been told it will cost about $1,800 to repair a leaking gasket in the front differential. Is this reasonable?

Asked by for the 2004 Toyota Sienna
looks like the engine and transmission has to be removed to repair this, the book time is about 15 hours, but get another estimate just in case
1 more answer
that is entirely to much