I may be posting in the wrong place, so sorry in advance, but i have a 1998 3500 dually, 4X4 longbed 12V. I was just curious what ring and pinion is in the rear of these things? it has a 5 speed manual in the truck and it seems like it runs pretty hard at 65mph, like 2000 rpm. im pretty sure the truck has the stock size tires on it. Already did the kdp fix, is there any other issues that you can think of to let me know what to look for. Also..... every once in a while the speedo when taking off from a stop will ramp up to like 90mph and then come back down to speed, checked the speedo against gps and its like 5mph off. Any help would be welcomed, and thanks in advance!