before the flaming starts, i'd like to say thanks for the advice. now with that said ... i've got a 93 s-15 jimmy that i am going to put toyota axles under later this year, but i want to know how hard ,and what is involved in doing a t-case doubler, i have the case from a 83 truck & an 86 4runner, can i put those together & make a doubler ? if so how hard is this mod ? i'll be putting this set up behind the gm trans. thanks again for the advice...

 

I would check out marlincrawler.com. with all the work you are going to do putting toy axles under a gmc, it seems like other than the adapter (dunno where you are going to find one, maybe advance adapters) to connect the transfer case to the gmc transmission it should be straightforward.
You can get the double transfer case adapter from Marlin, Advance Adapters, Trail Gear and Inchworm..those are the ones off the top of my head.

Trail gear has a good video: http://trail-gear.com/dualcase.html

 

^^ x2

Also, it's best to have 2 4CYL gear drive cases and slapping a 4.7 gear in the rear case. You are probably going to want to run 23 spline shafts throughout, assuming your GM motor is one with more grunt than the standard '86 Toyota mill.

Marlin is doing some stuff for the V6 chain driven cases for another option.

 

Everything you need to know:
http://www.marlincrawler.com/htm/tra...ickup_dual.htm

 

get the trans adaptor from marlin and find 2 top shift gear driven t-cases from a 85to88 4cyl truck or 4runner and get the adaptor to join them from inchworm gear

 

yep thats what i got is 2 top shift t-cases, dose any one have a link to inch worm? thanks

 

Why buy 1 part from Marlin and the rest from Inchworm? Seems silly to me, and costs more in shipping...

http://www.inchwormgear.com/store/

 

the website is www.inchwormgear.com cause inchworm gets the products faster to you than marlin and the owner answers the phone

 

I've called Marlin in the mornings this last week twice, and gotten my products within 3-4 business days. CA to CO. Answered in just a minute or two.

 

cool thanks for the info !!! i'll look into it. btw i've got a 4.3 vortec mill w/the 700r-4 trans. so it should be fun,fun,fun !!!!