i have a 1997 F150 4.6, mated to a 5 speed, 4x4 with a 8.8 differential in the back and I was driving home the other day and It felt like the pinion was spinning and the ring was missing a few cogs and would slip and then catch, jerking my truck. question i have is what gear ratio was it probably.... and If I should replace it to stock ratio or go with a lower ratio like say 3.83's or so. I can afford to swap both diffy's to lower gears. Any help would be great. thanks

 

Read the axle code off the driver's door jamb sticker - they are probably 3.55's, that would be 19 - or H9 if the rear is limited slip. 4.10's are the most popular swaps.