Gear reduction box

[Tlkennedy]

I know nothing about crawlers. I have a Tiger mini truck that has an underrated automatic transmission. Is it possible to install a reduction gear box between the automatic transmission and the rear end? If so what should I use if I wish to hear it down twice what is is now? This is not for rock crawling. Just for farm work.
Any help would be appreciated.

Terry

[Rocksurfer]

Is it a 4wd? If it is does it have a divorced t-case? If it is you might be able to add a second case if there is enough room. If it is 2wd you could add a divorced t-case from a Samurai and use it as a basic gear reduction.