ok, hopefully the title got some attention. im not sure if this should be in the newbie section but here it goes:

ive been doing alot of research, and i am slowly figuring out how im going to accomplish this. i know what im going to do as far as lift and motor, but im in a debate on axles. i want to keep the toyota 8.0's, building them (chromoly shafts, locked, geared, birfield eliminator, ect) i want this to be my weekend warrior, probably drive my '92 during the week and while working on the '85. anyhow, back to my question...

i want to do dual transfer cases, one stock geared, one 4.7's. when driving on the 40's, i would have one in low, one in high. lo/lo when mudding, trail riding. and when i make trips longer than 100 miles, i want to put stock or smaller tires on it and put it in high/high. is it possible to find tall gears for toyota 8.0's? preferably 3.07's or something close? and is my plan a bad idea? i've done all the calculating, and all the numbers match up exactly how i want them to, i just dont know the reliability of the set up. im in the army and im deploying next month, so i have another year ahead of me for planning/researching/getting anxious, and money isnt going to be a huge issue. im not going to blow all of my savings lol, i just have a dream i want to have done sooner than later, and i can always make more money, but you only live once. post any questions or more info you want from me. thank you for reading this novel lol

 

40s on a Toy is massive IMO. I THINK there were some taller gears offered, but nothing numerically higher than 3.50s-ish from what I recall. But with a tire that size, and that much leverage, your going to need a seriously beefed axle assembly. You may wanna think of swapping out for D60 front and D60 or 14 bolt rear... They have the bearings and beef to handle a tire that size.A Toy axle(Cruiser front, Cruiser FF rear) would handle it for a little while, but thats alot of strain IMO.....

 

i want to stay away from full width axles. i dont have my heart set on the setup i described above, just looking for more input. 5.29s will get the job done for what im building the truck for, but im stationed in the middle of nowhere, so if i wanted to take my truck out of town, camping up in the mountains, or possibly back home (800 miles) it'd be cool to still have the ability to do it quite reliably and just throw the big tires in a little quad trailer rather than trailering the truck any far distances.

 

ive seen plenty of toyotas with built toyota axles wheel hard on 40s. ive also seen built toyota axles and 37s break stuff. personally, i would stay away from higher gears. throw in 5.29s, and if you dont wana roll 40s down the highway (i would, but thats me) just get some cheap used 35s? i dont know about driving on the road with the case in lo/hi though. sounds like a bad idea to me. but im not familiar with anyone doing this

 

Going full width is the appropriate way of doing it.

 

don't go with a BFE:

 

all half tone gm axles? just me if i were to run something that large

 

The Toy axles are as beefy or beefier than domestic half ton axles. Cruiser axles are the same beef as D60s. Its astonishing the bearing and axle size difference between a domestic half ton and Toy axles. The only plus of domestic rear axles(D60 and larger) are the full float axles... Whick you can get in Toy axles from overseas. But since the aftermarket is so much more supportive of Dana stuff, you can get 35+ spline axles...

As far as being full width, if you have the money, you can have the diffs narrowed...

 

Even if the Yota 8" axles are "beefy" enough to handle a 40" tire, with it being that tall I'd want full width just for stability. Just my thoughts...

 

is there anybody with some advice on the setup its self, regaurdless of axles? would it be bad to run one transfer in low a majority of the time? or i could do a twin stick deal on the first transfer, but only run one shifter because there isnt a point in using the 4wd since its not hooked to anything, right? ive spent the last few months planning the suspension and motor, im just now starting to work on this idea so i havent put alot of time into learning about dual transfers yet.

 

The dual case set-up is simple. It takes one case and turns it into a gear reduction box. Which will decrease the output revolutions that would be going into the 2nd case, which reduce the output even more. So to get your crawl ratio, you would multiply. trans 1st gear ratio X 1st t-case ratio X 2nd t-case ratio X differential ratio.

To answer your question, both t-cases will have to have shifters. 1st one will be for hi and lo(since there is no physical output section on the case). The second has two shifter usually(one for hi-lo, the other for 2wd-4wd). You wont want to limit yourself and stick the 1st case in Lo and leave it. For trails, crawling, mud, sand, etc, you will want the various gearing options offered...

 

Cruising with just the front case engaged will put a lot of strain on the input shaft to your rear case most likely shearing off the input shaft making the truck immobile.

 

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