I am looking to get a lower gear ratio in my 84 4runner, and it seems like there are 2 options, double stacking the transfer case or regearing the existing one. It would seem that the more popular option is double stacking and I'm curious as to why... Does this option offer any advantage to regearing the case other than not having to open the "magic box"? It would seem to be the cheaper option in the end without having to get the adapter kit, second case, and altering the driveshaft. Any and all opinions would be greatly appreciated!

 

Two cases gives you more options for speeds(ratios). First case hi second case hi or low then first case low second case high or low. Add twin sticks to second case and you then have 2wd in all of these speeds. You also have the option of regearing both cases or just one. One case only changes the low range ratio. The stock high range stays the same. You can regear the diffs also.