Best bet on a transfer case will be a drop transfer case, like from SCS, profab, chain reaction or whoever you choose. I still have my old 18" drop case from my 5 ton k5 project. 1.55:1 with a 4:1 change-out
Using even a divorced np205 is out of the question at that much height.
Unless you run twin 205's with a bunch of fabbed up hangers.
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Take note, straight thru cases will be divorced unless you buy from SCS who sells adapters to marry them to a transmission.
Chain reaction, profab, etc are all divorced, meaning you'll need to run a jackshaft after the trans to drive it.
Meaning, you'll need a 2wd trans if you run divorced.
If you have any knowledge with automatics, that's easy enough to do, simply change output shafts and put a 2wd tailhousing on.
Would no advise running a 700r4 with 54" tires and 2.5 tons. It's gonna hate life in real short order unless you run like, 2 external coolers with electric fans on them
Since gas mileage has now exited the chat, you'd be better off with a stout 2wd th400, deep pan, and cooler. HD sprauges, etc.
2., any and every spring you run will have deflection at that height.
If you're wanting to run leaf springs, Trac bars are you friend. I can also send pics of what I was doing to give you ideas.
Suburban and k5 frames get weak in the middle under big tire, big axle stress, and Crack and break.
You'll need to weld up a sub frame for
A. Cradling the transfer case
B. Adding strength to your frame
C. Having something for the Trac bars to run off of.
D. Optionally, a step to climb up in it.
I welded up a subframe out of 2.5"x.250 square tube.
3. I figure this is my time to make a sales pitch.
I have some 24" lift springs. They're what's setting the k5 above 53's. Carrier LTD springs. Thats real deal sheit. Google those and you'll find their purchase price is around 3500.
I never actually got to use them, as I never finished the k5. I took it all apart and sold it. So...... if you are looking for a cheaper option on lift, 2500 bucks takes all 4 of them. That's mega cheap for that much lift.
I can send all the pics you want, video chat with you, whatever you need and palletize and ship them to you via whatever carrier you like.
Something to think on
They do actually have a little give in them. Believe it or not.
I have a contact for military surplus if there is no yards near you.
He sells his stuff cheaper than any other person I've met.
He's got a yard out in California.
But home base is in Florida.
He delivers, if you pay for drive time.
He sells detroits if you are wanting them.
If you're new to this mega truck stuff, I can recommend multiple names and contacts for parts and such, cheaper than the average red barn customs ripoff.
They're too proud of a bunch of heavy ass **** hardly nobody messes with.
The aforementioned contact in florida will sell all sorts of axles. Whatever you like.
Meritor, axletech 5k, Rockwell 2.5 ton, Rockwell 5 ton, Rockwell 7 ton with airlockers.
Clark 20 tons, Pettibone. Whatever you need !
I also have information stashed back on how to 4 wheel disc brake swap your 2.5 tons with part numbers and info.
Also, do yourself a favor and get 1 inch drive stuff.
I did.
I have sockets that go up to 4" in inch drive stuff. Just for the said heavy axles
Steering is another.
You'll need to plan for you're gonna do it.
I can guide you in the direction of DIY hydraulic assist or, just get the money for real deal full hydraulic steer from PSC.
Stock steering gear with no hydraulic assist won't cut it. It will L I T E R A L L Y rip the steering box off your frame.
I've seen it already.
Powerplants.
Unless we're returning back to 1965 where we used millions of gear reduction boxes and cases and 10 speed transmissions with a motor that made a whopping 180hp, you'll want a good healthy motor to lug all that.
And no, that wasn't an insult, lol I just mean there's two ways to move that rig.
Raw torque and gear reduction, or LOTS and LOTS of gear reduction.