I went through this with my 52. Since you have determined that you have a 6.17 single speed H110 (standard for the 1.5 tons), about the only easy option is the optional 5.43 ring and pinion set. Much is said here about rarity but I found a set( most recent part# 2352908) with a few phone calls.The set was made by Cobra Gears. I had it installed with all new bearings and seals and can say that it makes a big difference for me. With 7.5x20 tires/235 engine/SM420 trans it does 50-55 without screaming.
