Marlin Crawler Rear Chromoly Output Shaft vs. Stock
First some basic Q&A...
Applications: All 1979-95 Gear Drive 4cyl transfer cases
Modifications required: None, all modified parts are included for simple R&R.
Other compatibility: Fully compatible with stock shift hubs and stock cage bearings.
Does it use the stock flange? No, it uses our larger 30-spline flange. In fact, the shaft is stronger than stock flanges, so we had to design a stronger flange just for it (more on this later).
Two notches to stake the flange nut, double insurance (stock only has 1 stake).
Huge 24mm flange nut (stock is 20mm).
Retains factory oil pump, yet to increase strength, we reduced the pump inner diameter from 10mm to 6mm.
The common failure point is located right before the front output hub. When this failure occurs, you are dead in the water; no rear drive or front drive. This was our primary focal point, and we increased the material here by 52.3%! The second common failure point is just beyond the hub, so we added 45.2% more material here to compensate! Our 30-spline output shaft is seriously MASSIVE compared to a 27-spline shaft.
Now for some size comparisons...
|Feature||Diameter||Cross Sectional Area|
|Front Drive Section||1.17 in||1.38 in (+18.0%)||0.95 in2||1.45 in2 (+52.3%)|
|Front Output Hub||1.28 in||1.38 in (+7.8%)||1.17 in2||1.45 in2 (+24.6%)|
|Rear Drive Section||1.10 in||1.26 in (+14.6%)||0.83 in2||1.20 in2 (+45.2%)|
|Spline Diameter||1.09 in||1.22 in (+11.9%)||0.93 in2||1.17 in2 (+25.3%)|
|Thread Size||0.77 in||0.94 in (+22.1%)||0.47 in2||0.70 in2 (+49.1%)|
|Nut Size||20mm||24mm (+20.0%)|
Now for some pics...
Below is a comparison of the stock 27-spline rear output (left) and our 30-spline Chromoly rear output (right). Our shaft really makes the stock shaft look like a twig. As mentioned above, the front output section has 52.3% more material while the rear output section has 45.2% more. These were our two primary locations in terms of developing far more strength. Keep in mind that our shaft is made from Chromoly steel, so it not only has nearly over 50% more material to shear through, but it is much stronger material as well.
Our output also features the successful radiused hub design, adopted from our Xtreme Duty Chromoly dual case coupler. This is a great feature which helps pass more oil through the commonly overheated input pocket bearing.
Our output shaft also retains the factory Toyota oil pump system. This is important for longevity and functionality of your transfer case. Our shaft is so huge that we can incorporate this while hardly loosing any strength. Additionally, we reduced the oil pump inner diameter by 40% to increase strength and reliability. We realize you want to protect your investment and our output is designed to keep your truck running in top shape. Get there and back with Marlin Crawler!
We added an extra stake to make sure the flange nut stays put.
The stock 27-spline piece really looks minuscule in comparison. We use a 20% larger 24mm nut, bringing the thread size up by 22.1%.
And if it's massive size plus Chromoly alloy wasn't enough, we've also developed a seriously strong flange. We actually had to do this out of necessity: Our output shaft eats stock flanges for lunch. Check out our Heavy Duty "4-30" 4-pattern 30-spline flange featuring a 135% thicker cross-section:
This is what happened when we used a flange on our output shaft that had the same cross-section as a 27-spline flange:
Marlin Crawler's new 30-spline rear output shaft has 52.3% more material for the front drive section (common location for failure), 45.2% more material for the rear drive section (another common failure location), is made from heat treated Chromoly alloy, has improved pocket bearing oiling, retains the factory Toyota oil pump system, and includes two stakes for the 20% larger flange nut. It uses a 135% thicker flange with a 22.1% larger spline. It comes as a complete kit with all parts modified and ready for installation. Includes a new oversized bearing and an oversized EcoSeal to protect the environment. No modifications required, simply remove and replace the old components with our larger and stronger parts. Wheel in confidence with Marlin Crawler!