4 Speed Atlas install

One day in 2020 my phone rang. It’s Mark, from Metaltech. “Hey man, I’m taking the Atlas out of my Orange FJ. I’ll give you a good deal on it!”
“Let me think on…. OK, sending funds now”.
A week later, a pallet showed up with on it, a 4 Speed Atlas, 2 driveshafts and all the cables, shifters and brackets as it was removed from Metaltech 4×4’s 2007 FJ Cruiser.

4 Speed Atlas transfer case. The holy grail of Lo Lo.

The install took almost a week, few hours a night. Really not bad, but tedious. The shifter cables are by far the hardest to route and figure out, and the rigging of the cables was a bit challenging.

It obviously started by removing the already twin-stick modified transfer case. It came off easily.

Original case, previously modified with twin sticks

The install guide from Advance Adapters is about a page long, and doesn’t provide many details. Read the notes, you’ll see why later.
Removing the cross member bolts, and letting the trans hang down a bit helps, and removing the exhaust crossover tube is a must. This was fortunately easy on mine, and I had all the access I needed. For now.
The Atlas is a bit heavier than the stock case, and due to my lack of having access to a lift, everything had to happen from the floor. I purchased a Harbor Freight transmission jack and modified it to hold the Atlas at the angle I needed.

Strapped to the Harbor Freight transmission jack. A life saver!

Once I started maneuvering, I ran into two issues – the fuel tank had to come down, as it interfered with the angle I needed to spoon the case in with, and the rear of my transmission wasn’t compatible. There’s a bearing that some housings have that needs to come out, the spud shaft that connects the 750 trans shaft to the Atlas shaft wouldn’t clear it. Having seen that note would have saved me an evening of trying to figure out of why the case wouldn’t mount onto the transmission…

Once I removed the rear section of the transmission, and removed the seal I didn’t need, everything went smoothly. The transfer case bolted right up, I routed the cables and mounted the shifters in the brackets Metaltech had provided. Taking my time paid off, and I got everything routed right. Incorrect routing and weird angles can cause the shift cables to bind up, and making the thing hard to shift.

What’s nice about the 4 speed Atlas, is that the front driveshaft remains the stock length, but the rear needs to be shorter. Fortunately it was provided, and no additional down time was needed to get one made.

Install close up went pretty smooth, a few electrical mods were needed to make the truck’s computer know when it is in 4WD and Lo gear, those are picked up from two switches on the old transfer case. They tell the computer when to engage or disengage the ADD actuator, and when to disable the systems (TRAC etc) when in Lo.
I added a simple switch in the console for it, marked 2, 4 and LO. Some day I’ll get an appropriate switch for it, this will do for now, it works like a charm.

They call me “Shifty”

The transfer case is a 4 Speed, meaning it’s a regular 2 speed, like a stock one, but there is a doubler installed, allowing a combination of ratios, effectively making it a 4 speed. The ratios on my case are as follows:

1:1, Doubler Hi, Transfer case Hi
2.72:1, Doubler Lo, Transfer case Hi
3.8:1, Doubler Hi, Transfer case Lo
10.34:1, Doubler Lo, Transfer case Lo.

For comparison, the stock FJ Transfer case is 2.56:1, so even my “highest lo:’ is already lower than stock.

With my gear ratios and tires, that means a total reduction of 164:1 compared to stock 41.25:1
At idle in 1st gear, my truck will do 167 Feet per minute (1.89MPH)

Wheeling the Atlas is a learning curve. Due to so many different choices, it takes some experience to determine when to use what. At the Appalachian Roundup, the first outing with the Atlas, I found myself using Doubler Lo/Transfer Hi and Doubler Hi/Transfer Lo the most, with a few occasions using Lo Lo.

When geared so lo, you can almost let the tires do the work, and search the traction. Once they bite, you’re riding the elevator up your obstacle. Quite an experience.
Two downsides I see with being geared so low, is that if you need to move fast quickly, due to a weight shift, or a sliding vehicle, you won’t have the gearing to move. The other thing is that the brakes are working much harder to stop the truck, and keep it stopped. But that’s a matter of experience and knowing your equipment.
I’m looking forward to wheeling with the case more and learning it better. So far it’s been very cool, a great tool in the proverbial toolbox.

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