Are you the same person that had "Rear Air Ride" problems?? A while back,Did you get that fixed??
As for TALLER gearing,The transmisson does not have 12 gears,only Six it is just a 12 volt splitter. There are a couple ways to make that dog hunt. My opinion is just that an opinion and we all know what that means. If your truck was mine,
I would do two(2)things.But I'm a little off center in my approach on things.
First find out the rear gear ratio,It should be on a Metal Tag riveted to the Axle housing.I would not have a tendecy to trust Line Tickets,Build Sheets,SerialNumbers or the Stickers on the Drivers Side Door. Depending on Road Grime you may
want to use a putty knife or scraper along with some Aerosol Grease Cutter/Remover. I use CRC Carb. or Brake cleaner its
only helping cut the grease to find the Axle Ratio Tag,Could be attached to one of the bolts that holds the pumpkin in to
The tag gives you info: Manufacture,Ratio etc. then you could find a taller gear set at a Truck Salvage/Junk Yard or a
complete rear Housing & all. Like I stated above "MY OPINION" That Tranny would become a "Friggin Boat Anchor" real quick.
If you like or don't mind shifting, There are Hundreds of Rebuilt 6,8,10,12,13 & 18 spd.O.D. Real Trannys around "Cheap"
Depending the word Cheap??? From $800.00-$2,500.00 With a Warranty. There are Allison Automatic's Rebuilt out there also.
Not so Cheap. Well opinions are cheap too.