Exploring the New 4.70:1 XD Technology

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Exploring the New 4.70:1 XD Technology

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Marlin Crawler, the inventor of the 4.70:1 ratio in 1995, unveils their new Xtreme Duty 4.70:1 Low Range Gear Set, further establishing their stronghold on the Toyota transfer case market as the world-leader in strength, reliability, performance, and design.

Twelve years since it's creation, the most successful and longest lasting Toyota low range gear set of all time has been reinvented. Please take a moment to explore the technology of the most feature-rich gear set in the world...

Marlin Crawler 470:1 XD


  1. AISI/SAE 8620 Steel Alloy Material
  2. Total-Spline™ Input Technology
  3. Wider Countershaft Teeth
  4. Oversized Countershaft Shank
  5. Slow Speed Oil Transfer System
  6. Mainshaft Cage Bearing Oil Pump System
  7. Countershaft Cage Bearing Oil Pump System
  8. Tapered Shift Hub Lock System
  9. Increased 63/32N Bearing Oiling
  10. New Lighter-than-stock Design


1. AISI/SAE 8620 Steel Alloy Material

Our previous gear set was cut from 8620 steel alloy, and our new Xtreme Duty gears settle for nothing less. We only use material that is recognized by the American Iron and Steel Institute (AISI) and the Society of Automotive Engineers (ASE). Marlin Crawler means Quality.

  • Excellent toughness, hardness, and wear properties far superior to OEM material.

2. Total-Spline™ Input Technology

Marlin Crawler 470:1 XD Total-Spline

Marlin Crawler invented the Total-Spline design in July of 1995 and began producing them in 1999. Since then, the number of broken inputs and stripped out couplers have been drastically reduced. This same technology is featured in our new Xtreme Duty 4.70:1 Gears.

  • The only gear set in the world with Total Splines.
  • 65% Longer Splines - By far the longest lasting and the most difficult to strip.
  • 15% Larger Diameter - Can handle much higher torque loads without failure.
  • NEW! Now features the same oil pump as our countershaft! (see #7 below)
    NEW Input Oil Pump System!

Additional Total-Spline Input Design Information

Total-Spline™ Technology is an exclusive Marlin Crawler feature. Marlin invented this technology in 2000, which improves the performance of both a Low Range Gear Set and a Dual Case Unit as it addresses critical weak-links of both products at the same time.

Two benefits in one

1. The Marlin Crawler 4.70:1 gear set is stronger than any other gear set mainly because the input is the weakest-link of the transfer case. Marlin Crawler's Total-Spline is the only design that has removed the factory "fuse" or neck-down/taper of the input gear resulting in a much stronger product than both stock or any aftermarket gear set.

The Total-Spline design offers 65% longer splines and a 15% larger minimum diameter
making it the longest lasting with the highest torque load rating available. It is the only
Toyota low range gear set in the world that addresses the problem of stripped splines.

2. Having "total" or full-length splines means that more splines are in contact with the Coupler of your Dual Case Unit. This is important because the spline contact between a t/case input and a Dual Case Coupler is the weak-link of the Dual Case Unit. Therefore, by using a Marlin Crawler Total-Spline gear set you are also minimizing the risk of stripping out the Coupler of your Dual Case Unit.

Here is a stripped out Dual Case Coupler. You can see how not all of the splines were
in contact. If a Total-Spline Marlin Crawler input had been used instead, this Dual Case
Coupler would have lasted longer.
Likewise, it would be able to withstand higher torque loads
due to the increased surface area and load spreading of a full 100% spline engagement.

Proven Performance

The Total-Spline technology is so impressive that we have successfully ran a 21-spline version in a dual cased V6 Tacoma with 220 ft-lbs of engine torque. In comparison, non-Marlin Crawler 21-spline inputs have an engine torque limit of approximately 170 ft-lbs (about 30% lower). Our 23-spline version has survived a Tundra V8-powered dual cased X.R.R.A. Competition Buggy with 315 ft-lbs of engine torque for multiple seasons without input or coupler failure. While we don't advocate using 21-spline setups in V6 rigs, the fact remains that the Marlin Crawler 4.70:1 Gear Set is seriously strong and works extra hard so you don't have to!

3. Wider Countershaft Teeth

Marlin Crawler 470:1 XD Wide Teeth

The weakest spot of the countershaft just became a whole lot stronger. The new Xtreme Duty Gear Set features extra wide teeth to spread the torque load where it matters the most.

  • This is the weakest spot of the countershaft.
  • 42% Wider Gear - Soaks up torque like a dry sponge.

4. Oversized Countershaft Shank

Marlin Crawler 470:1 XD Oversized Shank

Just to make sure these Xtreme Duty gears can live up to their Marlin Crawler name, we increased the diameter of the countershaft shank. Marlin Crawler Gears are truly remarkable.

  • Improved torque and shock loading.

5. Slow Speed Oil Transfer System

Marlin Crawler 470:1 XD Low Speed Oil Transfer System

Our new Xtreme Duty gears are the first gears in the world to feature a specifically designed low speed oil transfer system. Think Crawling. Crawling slowly limits the amount of oil available to the mainshaft cage bearing. As the new Xtreme Duty low speed gear slowly rotates, oil is caught and lifted up where it is deposited right into our cage bearing oil pump system (described below).

  • World's first low speed gear oil transfer system.
  • Prevents oil starvation of mainshaft cage bearing and input pocket bearing while Crawling.

6. Mainshaft Cage Bearing Oil Pump System

Marlin Crawler 470:1 XD Cage Bearing Oil Scoop System

This exclusive Marlin Crawler Oil Pump system is a revolutionary way of ensuring the mainshaft cage bearing keeps a maximum amount of gear oil under all driving conditions. Wether freeway driving or 1,372:1 Rock Crawling, it is important to keep all bearings lubricated.

  • The only gear set in the world featuring an integrated Low Speed Gear Oil Pump.
  • Increases oil to all mainshaft bearings including the 4WD idle gear cage bearing, low speed gear cage bearing, and the input pocket bearing.
  • The most efficient gear set on the planet - ideal for mixed trail/highway use.

7. Countershaft Cage Bearing Oil Pump System

Marlin Crawler 470:1 XD Countershaft Oil Pump System

This all-new integrated countershaft cage bearing oil pump is truly amazing. When the countershaft gear meshes with the low speed gear, tremendous pressure is created between each tooth, and the surrounding gear oil is squished out of each bottom landing. What we have done is created two tunnels (180° apart) for this gear oil to be transferred straight to the cage bearing where it is needed.

  • The only gear set in the world featuring an integrated Countershaft Oil Pump
  • Extreme climates demand the Xtreme Duty Gear Set.
  • Snow and Mud often prevent airflow around the transfer case - keep oil circulating when the air is not.
  • The Xtreme Duty Gear Set is by far the coolest running low range gear set on the planet.

8. Tapered Shift Hub Lock System

Marlin Crawler 470:1 XD Tapered Shifter Lock System

Toyota wasn't playing around when they built a tapered shift hub lock on each and every low range gear set ever made: It prevents accidents and can even save lives. Imagine Crawling up a very steep incline. You get higher, and higher up, 30-, 40-, 50-feet and higher. Now imagine your transfer case suddenly pops into neutral! Don't let this happen to you! Other gear manufactures overlook this absolutely critical shifter locking feature and Marlin Crawler refuses to sell dangerous gear sets!

  • It's a very serious issue that too many people take for granted. Protect your investment as well as your life.

9. Increased 63/32N Bearing Oiling

Marlin Crawler 470:1 XD 50 times more oiling capacity

The countershaft is supported by two bearings, and we did not forget about the 63/32N ball bearing. The new Xtreme Duty Gear Set features a dished countershaft near the 63/32N bearing yielding a whopping 50-times more open space beneath the bearing. This allows for massive oil circulation around the bearing, which is important when the gears are used behind a restrictive dual case adapter in an Ultimate setup or when the oil is shifted away from the bearing on steep inclines or declines.

  • Much faster heat transfer from the bearing to the oil.
  • Much faster lubricating recovery when oil is shifted back to the front of the case.
  • The first aftermarket gear set that allows for complete through oil cycling from one side of the bearing to the other.

10. New Lighter-than-stock Design

Marlin Crawler 470:1 XD Lighter than stock Toyota gears

You read that right, the new XD gear set is lighter than the stock low range gear set! Amazingly isn't it? At just 15.1 pounds, we've added technology and removed fat. Less rotational mass improves acceleration while reducing the load on the bearings. The result is a more responsive gear set with longer lasting bearings.

  • 8% weight reduction puts XD gear set lighter than stock gears - the lightest gear set on the planet!
  • More responsive to RPM change - Less resistance, improved acceleration.


After examining the most feature rich and technologically advanced Toyota RF1A low range gear set in the world, we are certain you will agree that the new Marlin Crawler Xtreme Duty 4.70:1 Gear Set is on a completely different level far, far above all the rest. There simply is no comparing a Marlin Crawler with any other. Marlin Crawler