Trouble with Tamiya M48A3

I am having a problem with the rear engine grill. It seems to be too big. If I position it to fit properly in the upper hull, then if hangs over the tops of the rear lights. If I position it on the lower half, then it sticks up above the top of the upper half. If I try to force it into the correct position on both halves, then the two halves are not flush with each other.

Have others run into this and is there a solution without whittling this grill into the correct size?

Never had a problem with it in the 3 I have built. It may be in the way you are postioning it. The upper portion of the hull should overhang the rear doors slightly. It should not be totally flush. Should look like below.

Hope that helps out.