I just replaced the engine in my xj 4.0 about 2000 miles ago and today when i went to start it, theres a super high pitch whining coming from the underside of the engine, i haven't had time to look at it yet, but i'm really irriattated. Any healp would be nice. There is no grinding or crunching and it still runs fine. Its an automatic and the noise seems to decrease when i accelerate until i let off a bit on the gas pedal, then it goes back to the same.drove it for 15-20 and it never stopped