Atlas case in a GMT 400 (99 Yukon?)

[Zombie]

Inspired by Greg's Dual Sport, and frustrated with the stock front end on my 99 Yukon, I'm starting to put together a project list for solid axles...

I've been been looking at the ORU kit, and this kit from Fabworx http://www.fabworxoffroad.com/low-boy-3252-kit-for-dana-60-sac/

Ideally I'd want between 3 and 4 inches of lift, no taller than a 35" tire, probably close to a 33". I'm not looking at a shackle flip, as I'm planning to tow a 21' boat behind it, and i"d prefer the tension configuration remain intact in the rear.

I also have the Autotrac T case to address, and I'm considering and Atlas to solve it... contemplating hiding the shifters in the factory center console. I do not want an OEM floor shift case as I'm REALLY fond of putting my foot on the transmission tunnel with the cruise set on road trips - NOT IN TRAFFIC, before someone criticizes my safety. I know in the S10 trucks of a similar year, there are challenges with running a non-stock geared case... anyone know if I'd need custom programming for an aftermarket case with this truck?

Other plans include front and rear bumpers (which I'll make) including a tire and stuff carrier on the rear, on board air with tanks mounted in the stock spare location, and a winch.

What else haven't I thought of?

 

[Bart]

I'm not sure why you'd want to spend the money on an Atlas unless you're doing front and rear digs. There are other heavy duty transfer cases out there that are a lot less expensive. To each his own, but I don't get it.

 

[bryson]

Unrelated to your T-case question, but are you using a 60 or 44 front? Is your Yukon 6 or 8 (Yukon XL) lug? Just wondering if your lug patterns will match, or if you have rear axle plans as well.

I like the idea.

*edit*

You mention rear shackles, so I'm assuming it is a Yukon XL 2500 (The short Yukons are coils/bags in the back, aren't they?)

 

[Greg]

I'd love to see your take on a similar vehicle as my GMC! I dig the idea of a low-slung, solid axle Tahoe too... very cool!

The Atlas is awesome, but I think Bart is right... unless you need the strength, gearing and F & R digs for rock crawling, it's overkill. Plus DD'ing a Atlas is pretty brave, IMO. I know it's been done but I personally think there are better options out there. How about a NP 243? It's what I have in my truck, it's a push-button version of a NP241. I have a couple of dash-mounted buttons to shift the t-case and it works fine. Some people don't like having a electric controlled t-case and swap them out for a 241, but so far and with almost 200k miles on mine it's working fine. You'll need the wiring harness, the ECM that manages the t-case and the buttons... but they should be easy to find

Also, with the longer front springs I'm betting you'll need a quality anti-sway bar. My truck is pretty loose, but manageable... longer springs in the front will add even more body roll. Keeping your rear shackles inverted will help keep body roll in check, but I imagine you'd still have some. Speedway Engineering makes custom anti-sway bars, which is what I'm planning on eventually (if it doesn't sell first.). - http://www.1speedway.com/Swaybars.htm

 

[Zombie]

Bryson, it's an OOBS truck, the 99 Yukons and Tahoes were still GMT 400 platform so I'm leaf spring in the back.

I'm almost open to a D44 front, but I am attracted to the brake upgrade of the one ton axles, as well as the durability of kingpins, and the rest of the 60 stuff. I'm well aware that with 35s and not crawling, I won't NEED 60s, but I really like the idea of a "set it and forget it" solution, heavier duty than the truck will ever need. If I go 60, I'd go 14FF in the rear as well.

To discuss the T case, I'm not sure I want to spend the money on an atlas either. I want a solution that will maintain the OEM speedometer, and not be an auto track case. I'd be interested in discussing other potential solutions... just thinking of the atlas, as it was one of the things I wanted to do on my ZJ, but never did. If it's possible to swap in a non-autotrack case without massive rewiring, I'd be interested in that as well... the info I've found in searching seemed mixed, and created more questions than it answered.

 

[Zombie]

I posted the above before reading your reply Greg...

My current case is the autotrack pushbutton... any idea how much wiring I'd need to change to go non autotrack?

I'm certainly planning a swaybar... I'd initially envisioned finding a way to make the stock on work (might not be possible) and switching it out for a police package or aftermarket thicker bar. I'd also like to keep the bar in the rear, which might take some creativity, but should be doable... maybe I'll get lucky and find a 14FF from a burban with a rear sway bar...

I'm very much in the planning phase here, so I appreciate the discussion... Thanks guys!

 

[UPNO4]

This sounds fun Trying to remember the other T/case options from that Body style may not have to do much in the way of wiring as there are some non auto track options in those years. I am thinking but nothings coming maybe a few days in Moab will jog my memory

 

[Greg]

I posted the above before reading your reply Greg...

My current case is the autotrack pushbutton... any idea how much wiring I'd need to change to go non autotrack?

I'm certainly planning a swaybar... I'd initially envisioned finding a way to make the stock on work (might not be possible) and switching it out for a police package or aftermarket thicker bar. I'd also like to keep the bar in the rear, which might take some creativity, but should be doable... maybe I'll get lucky and find a 14FF from a burban with a rear sway bar...

I'm very much in the planning phase here, so I appreciate the discussion... Thanks guys!

I don't know how much (or if any) of the Autotrac wiring and push button stuff would work for the 243, it's quite possible the buttons would work. Otherwise, I'd plan on just using the ECM and wiring from a NP243.

Do your buttons look like these? This is my truck...

The stock anti-sway bar will be pretty stiff, I couldn't make mine work after the solid axle conversion. I'd like an aftermarket one from Speedway that wasn't too stiff, that I could leave hooked up for off-road travel. Here' my ideas regarding an aftermarket ant-sway bar... Frame is 34" wide, add 3" per side for hardware for 40" total... 39" is perfect.

 

[Zombie]

Greg, My dash looks just like that, but has the "Auto 4wd button on the bottom part of the 2HI button... forgot to snap a pic thismorning, will get one up later.

 

[Zombie]

My next question, I've pretty much settled on the ORU kit, with some stock replacement front leaves to keep me at about 3"s of lift...

The outstanding question I have now is what 60 should I shop for?

There are two options with the ORU kit, a 32.x" spring pad width, and a 36.x pad width. IT seems to me that for a vehicle that will see light recrational use, and do some light towing duty as well, the wider spacing might improve the stability on the street, possibly sacrificing articulation... and since this isn't a rock crawler, I'm not too worried about that...

Pros and cons of the 36" pad spacing?

 

[Chevycrew]

Pro of 36... availability, con... wheel backspacing is critical.

 

[Zombie]

Can you expand on backspacing? My goal is to run a 17x9 wheel, with as close to stock H2 offset as I can get in effort to keep more of the tire under the truck, and not have to run a burly flare or be stupid wide....

 

[Anchor_Mtn]

I miss my old tahoe.
1979 ford HP D44 front axle with 4.56 gears full high steer(35.5" Spring pad center, 8x6.5 bolt pattern)
D70 rear 4.56 gears
Alcan springs all around(52" front, 54" rear)
TJM Winch Bumper with 9000lb Tabor Winch
Custom Sliders
35" BFG ATs on H2 wheels
No front sway bar, factory rear swaybar
Manual Shift 241 t-case

Tires didnt stick out past the body and didnt rub the springs. The truck is still alive and running around NE PA with a 5.3L motor now.