No.  If you are under age 50, your maximum elective deferral to the SIMPLE IRA is $12,500 and your maximum combined elective deferrals to both plans is $18,000.  If you have already deferred $10,400 to the SIMPLE IRA at the first job, you cannot defer more than $7,600 at the new job without making an excess deferral.  You must inform your new employer's plan administrator that you have already made elective deferrals of $10,400 in 2017 at another employer so that the new employer will cut off 401(k) elective deferrals when they reach $7,600.