ask the glass company before the work about waiving the deduct, some will some wont... windshields only leak after somebody replaces one and installes it incorrectly... do a water leak check... find a helper. one inside and one out. take the hose on the outside and a good flashlight on the inside. take the "A" pillar mouldings off. take the kick mouldings off, look inside the a pillar and inside the door jamb where the door hinge bolts to the cab. water can come in around the hinge bolts or at the upper part of the "A" pillar where the roof is welded to the pillar. is you pull the upper seal off the drip rail i have seen small holes form over time and cause water to enter. water coming out of the hose at wall pressure is enough, dont make a leak...just run water over the top of the truck, if it is leakign it will come in. a good tip is to take the carpet out (to let it dry also)soak the crap out of the top, and even get a small low pressure sprinkler and put it under the truck to cheak for water entering from under a seam in the floor. with the carpet out there is no way not to find the leak, good luck. ps dont ever use silicone on the windshield, it will never seal up. allways use a good body seam sealer on body seams, and go to the glass shop to have a strip of urathane sealer backfilled on the glass to seal up leaking glass.