ONE QUESTION. I HAVE A 2005 GMC SIERRA 4X4, ITS A 4.8 L V-8 WITH A 4L-60 TRANSMISSION, WHEN I AM DRIVING ON A STRAIGHT AWAY AND OR UP A HILL WHEN IT SHIFTS FROM 2ND TO THIRD I CAN HEAR A SLIGHT CLUNK, METAL HITTING METAL, VERY SLIGHTLY MOST TIMES, I GOT MY TRANSMISSION FULLY FLUSHED, THE PAN HAD NO RESIDUE, METAL CHIPPINGS, NOTHING, IT WAS CLEAN AS A WHISLE, NOW IT HAS DONE THIS EVER SINCE I BOUGHT THE TRUCK, AND IT NOW HAS 33,000 MILES ON IT, AND MY QUESTION IS...........IS THAT NORMAL, OR IS IT NOT?

 

Mine has the same light clunk, it is normal.