Dual T-Case Noob Question

Gearing up (heh) for a SAS build with my son over the next year with an 01 Tacoma Xtracab, 5VZ V6, auto trans. The idea is 1 ton axles on 40's, with Sky's SAS leaf setup.

I'm hoping someone can shed some light on adding another t-case without dropping $2,000+ on a setup like the Trail Gear Trail-Creeper or Marlin Tacobox. Is purchasing just the adapter plates and a junkyard t-case an option?

Thanks!

 

Nope got to pay to play.

TG plates are $775 or so and 4.7's are $600 if you want to go the junkyard route and source your own case.

 

Thanks! So on the other end of the spectrum is an atlas. Is there an advantage to going with a single atlas vs dual cases?

 

Atlas is quite a bit stronger and will bolt to your a340f if you swap an AW4 tailhousing and shaft into it.

 

You’ll need 2 adapters. The 5vz to gear driven case adapter and the dual case adapter. Looks like this kit has both.
https://www.trail-gear.com/index.php/tacoma-dual-case-adapter-kit.html

You’ll also probably also want to convert the second case to 23 spline as well
https://www.trail-gear.com/index.php/catalog/product/view/id/6301/s/23spline-2-28-input-gear/

IMO you don’t really need the 4.7 gear set. I’ve been crawling for 7 or 8 years with stock gears in both cases and I can only think a handful of times where 4.7 would have been a luxury but not necessary, then again I am on the east coast.

The assembly is pretty straight forward. There’s good instructions online, iirc marlins are better then trail-gear. The cases them selves are pretty bullet proof regarding bearings and stuff. Out of all the used t-cases I’ve bought only one needed a rebuild and it was cheaper for me to just buy another t-case and use the bad one for spare parts.

My 23spline dual case set up has been in 2 v6 rigs and I’ve blown up my fair share of diffs and axles but never a t-case failure. I do run smallish tires though (35”)

 

Thanks! What ratio are you running?

 

I run 5.29s in the diffs and the stock 2.8 gear set in both t-cases.

Some guys on pirate4x4 were breaking Toyota t-case output shafts on tons and stock diff gears. I think you need to gear down the diffs for the t-case to survive. I don’t really know anything about 1-ton axles though

 

Big help. Thanks

 

One more question: for the dual case setup, using the Trail Gear adapter kit, what transfer case should I be sourcing?

 

You’ll need 2 gear driven, top shift t-cases from a 4 cyl pick up or 4Runner (forward shift can be converted to top shift but that’s more work and/or money) This is also going to convert you to passenger side drop.



There is a way to use one gear driven case in front of the stock Tacoma chain drive case but I’m not sure on the details
For that.

How to identify t-cases
https://www.marlincrawler.com/tech/transfercase/transfer-case-bible

 

Just go atlas. Stronger and with the auto you don’t need the super low gearing. Comes out to a similar cost in the long run of parts when building a lefty and will be 10 times stronger. I went dual cases with 2.28 crawl box and 4.7 tcase and only use the the 4.7 and will be soon upgrading to an atlas in the 4.3 of 5.0 flavor. Plus you get front digs with the atlas

 

Are you going driver or passenger drop front axle?

 

^^^^ This

More then likey will be running the crawlbox and chain tcase combo vs twin gear driven cases. In which case go for the 4.7s. as a 2.28 combo gives you 2.28/2.56/5.83 vs 2.56/4.7/12.03

Alot of good crawlbox info we have collected in this thread. https://www.tacomaworld.com/threads/official-crawlbox-bs-thread.422186/

 

Great question. I'm sourcing a dana 60 and prices are ridiculous. Nature of the beast I guess. Ultimately I want a high pinion kingpin. Still unsure which side the diff is on!

 

Once you pin down which drop you are going to go with, that will decide what combo of cases you need

 

well stop looking for kingpin ones and get late model super duty 60s. I found mine for 250 bucks and matched a 14bolt for 100.

 

Isn’t all Ford stuff driver side drop? I’d say start looking for a Chevy 60. They have the diff on the right so you can avoid using the weaker chain drive case in your dual setup.

 

That's a great price!!

 

https://www.tacomaworld.com/threads/transfer-case-transfer-cases-in-first-and-2nd-gen-trucks.345652/

 

yea, it would depend on the way you want to go. I broke a few toyota dual cases with the stock 22r and 37s lol.
my last build on my fj i just went with an atlas to not deal with it anymore. so any front axle was good