It's 4:10 rear gear, and it happens when the trans shift form 1st to 2nd, 2nd to 3rd mostly under load
. The last time I had fuild changed was at 132,800 miles, and now have 144,600 miles on the truck.
2001 2500 4X4 Patriot Blue,Air-Raid Edge Juice, Bully Dog Exhaust, FASS Fuel Pump