I HAVE A 2004 HERTIGE F150 EXT-CAB 4X4 WITH A 4.6 I DID THE HYPERTECH 87 OCTANE REPROGRAM CHANGED MY SHIFT POINTS AND PUT ON A K&N FITERPAK NOW UNDER HARD ACCELERATION I HAVE WHHAT SOUNDS LIKE A RUBBING OR SLIPPING NOISE FROM 1nd TO 2rd AND I CANT FIND ANYTHING WRONG !!!!!!!! THIS HAPPENED TO ANYONE ELSE??????????

 

Time for a Goodyear Gatorback Belt. Fixes the 1-2 shift squeak.

Most people with performance problems have this problem until they replace the belt.

-Joe