Will an Xfer case live up to this ???

[The_Blue_Coyote]

Asked a simular ? before, and the consenus was run the 9" - after checking into it, it will not be feasible.
SO, here is my two part question.
Application is a 1984 Toyota 4x4 used as a Class 7s desert race truck. Need to go faster over big whoops & rought terrain. Have the suspension, but lack power. A 22r (web cam, weber 38, thorley, etc) will only put out so much HP. Since speeds top out a 60 +/- axle gearing is the way to gain the power back. From the oldtimers I learned that the ideal final gear ratio needs to be in the 6.00 to 8.00 range.
Options are:
1. Run the 4.88's, and drive in 2nd & third <down side, hard on trannys, and W56 are $$>
2 Run 5.29's and convert to a R151 <again, big $$ and potentially hard on trannys>
3. Ford 9" w/ 6.50 's <down side, big $ to build & maintain - prefer to stay all Toyota, have lots of spares>
4 Toyota V6 diff w/ 5.71's <down side, poor reliability, gears are supposed to be too weak>
5 Swap to 3.54 / 3.90 / 4.10's and run the truck in 2lo (8.07+ final ratio) <down side, will the Xfer case live up to this???>.

Am currently doing #1 - already  two tranys. #2 seems like it will kill the trans, just takes a little longer and more $ to replace. #3, not going that route.
Which leaves me to # 4 and #5
Precisoin lists some for a V6. Pinion shaft is the same as a 9". And 5.71 has a few more pinion teeth that 6.50. Can the 5.71's me made to live?

And by far the easiest would be to run the truck in 2lo. For long runs, can shift back to 2hi, but 75% would be 2lo. But will the Xfer case take this prolonged hard use? Will the gears overheat, anyone ever add a Xfer case cooler?

Any words of advise from Marlin the xfer case guru?

[mr4x42u]

I think the t-case wouls hold up..I think a r151 turbo tranny would be a great help too..They are way stronger and have the lower 1st gear,,That might help out..I would for sure stay with a toy rear over the 9in..Toy v-6 third may also be the way to go if you can get the gears you need??

[YotaYota]

I Run a spooled v6 3rd in the rear, and locked v6 3rd in the front w/ 5.71's, I beat them pretty hard, I herd the key to keeping the 5.71's alive is to have the gears set up a little "tight", I had a friend set mine up.

[The_Blue_Coyote]

A little more info for you..
Rears are all V6 diffs with Yukon spool, Marlin crush sleeve. Gears are broken in properly, and run in Lucas oil.

Yota - what brand gears do you run, and what size tires?

With dez racing, you need at least 2 of everyting. Buying 2 151's is out of my range. W56's and G52 I can still get for 100 to 250 each. What kills the trannsy is the hard use in 2nd and 3rd gear. Running in 4rh 1:1 will alleviate that. So the additional reduction needs to be either in the rear end or an underdrive (huge $ or use the stock Xfer case).

[YotaYota]

Im runnin persicion gears, w/ 37 inch tires, ive seen somebody runnin 39" iroks on yota axles, not sure what gears he was runnin but he said he has good luck w/ it.