2003-2009 4.0-liter 4Runner|
2005-2015 4.0-liter Tacoma
2006-2014 4.0-liter FJ Cruiser
- requires fuel tank modification
2010+ 4.0-liter 4Runner
What is a TacoBox?
The TacoBox is a compact reduction unit based on the famous 25-year time-proven Marlin Crawler Dual Case 'Crawl Box' design and is inserted between your transmission and transfer case.
In order to do this, two adapters are used to convert the bolt patterns of both your transmission and transfer case. The first adapter is our newly updated 25% stronger 5/8" thick USA-made Billet Aluminum MC30, MC31, or MC32 Adapter to mate a Marlin Crawler Reduction Housing behind your transmission. The second adapter is our 6th generation USA-made Billet Aluminum MC09 or MC11 Adapter which bolts to your original transfer case. The result is the Marlin Crawler TacoBox™, a fully assembled Dual Case Unit ready to be installed into most 1995 and newer Toyota 4WD drive trains.
The heart of the TacoBox™ is the rear adapter. This 6th generation Dual Case Adapter features everything you'd expect from the quality and reliability of Marlin Crawler. First we machine a block of solid Billet Aluminum on a CNC mill and then install our Maximum-Capacity 32-ball Double Roller Bearing, the largest and strongest mainshaft bearing ever used in a Toyota Dual Case and the bearing that has powered our Daily Driver, competitive Rock Crawling, and Desert Race vehicles since 1999. Next we fit a Heavy Duty Oversized Heat Treated Coupler for the ultimate in strength and reliability. Finally, this 6th gen design carries over our Heavy Duty lower cage bearing from our Xtreme Duty adapter line, which is 84% larger with a 52% higher load rating. Unlike other lower cage bearings, our 'XD' bearing has never been reported to have overheated in very deep snow and mud wheeling. A significant amount of oil flow design has been incorporated into this adapter to ensure steady highway operation even while towing uphill in hot climates.
The front adapter is much more simple than the rear, but plays an equally important role. It also has an exclusive Marlin Crawler heat treated & oversized coupler with increased spline length and contact for maximum strength and longevity. This front adapter allows our TacoBox to be bolted directly behind a 1995 or newer, 4-, 5-, or 6-speed, Automatic or Manual Transmission, thus completing the package!
Our TacoBox features the same exclusive advanced reliability components and designs as our world famous MC07 and MC08 Hilux Crawler kits. As such, the TacoBox is built atop more than two centuries of Dual and Triple Case research and development. We invented the world's first Dual Case Tacoma at the turn of the century and have been designing and building late-model chain drive type Dual Case setups ever since!
Required modifications include contracting with your local driveline shop to lengthen, shorten, and rebalance your front and rear shafts, lengthen the wires of your transfer case shift solenoid (if applicable), lengthen 6mm vacuum hose to shift base and solenoid (if applicable), and install a new shift handle into your interior by cutting a 2.5" hole in the center of your cab and modifying your center console. For automatic owners this usually involves modifying a cup holder, coin slot, or cubbyhole. For manual owners, a simple modification to your transmission boot is all that is needed. Please see our Interior Shift Handle Installation Picture Gallery for ideas!
No factory crossmember modifications are required, however, modifications to under belly skid plates may be required depending on brand. The TacoBox includes provisions for an additional transfer case mount which is optional but when incorporated is a great addition to help lengthen the lifespan of your engine mounts! If desired, we offer a Heavy Duty 6cyl wide-style OEM Toyota mount here.
We also offer in-house full turn-key TacoBox installation including synthetic gear oil and interior shift handle installation. Please be aware that our installation department is typically booked far in the future. Please give us a call for details at (559) 252-7295 or (888) 942-7295!
What does the TacoBox do?
The TacoBox has three shift positions that may be engaged from a stop at any time:
- High: High Range is 1.00:1 so shaft speed & torque enters and departs at the same rate and is used for normal City and Highway driving. The ECU and all associated systems such as cruise control, traction control, stability control, the full ensemble of Toyota Safety Sense, ABS, ATRC, and Crawl Control, function normally. City and Highway Fuel Economy is unaffected. The truck will feel and operate 100% like factory both on-road and off-road, 2WD or 4WD. The TacoBox is simply bypassed.
- Neutral: Neutral is a fully neutral position and allows for such things as flat towing without any damage to your transmission. In fact, many electronic shift Toyota transfer cases do not have a Neutral position. The TacoBox fixes that.
- Low: Low Range is our famous Marlin Crawler 4.70:1 ratio. When engaged, your truck instantly becomes 4.7-times more capable and will blow your mind at how much control the truck has and how easy it gets up and down obstacles.
The end result will look like this:
Engine > Transmission > TacoBox > Transfer Case... thus transforming your 2-speed (High/Low) factory transfer case into a 4-speed TacoBox-equipped transfer case as follows:
|Factory 2-speed T/Case|
High Range (1.00:1)
Low Range (2.57:1)
|TacoBox-equipped 4-speed T/Case|
High Range (1.00:1) ← TacoBox in High, T/Case in High
Factory Low Range (2.57:1) ← TacoBox in High, T/Case in Low
TacoBox Single Low (4.70:1) ← TacoBox in Low, T/Case in High
TacoBox Dual Low (12.08:1) ← TacoBox in Low, T/Case in Low
In a 5-speed transmission example, the truck will now have 20 different forward gears and 4 reverse, making it a 24-speed truck!
Marlin Crawler TacoBox undergoing installation
If you have 33" tires, a 3.50:1 automatic 1st gear, and a 4.88:1 ring and pinion ratio, then your automatic truck will look like this in first gear...
|Final drive ratio *||17.08:1||43.90:1||80.28:1||206.31:1|
|Speed at 6K RPM||34.5 MPH||13.4 MPH||7.3 MPH||2.9 MPH|
|Speed at idle||4.60 MPH||1.79 MPH||0.98 MPH||0.38 MPH|
|Torque at idle **||171 lb-ft||439 lb-ft||803 lb-ft||2,063 lb-ft|
* Static ratios listed. With an automatic, there will be additional reduction from the torque converter when not electronically locked. At low speeds, this adds for an additional 2- to 2.5-times reduction depending on ATF temperature and drivetrain load.
** Torque at idle is calculated from a conservative estimate of 10 lb-ft of torque output generated purely from the stored potential energy of rotating engine components and ignores drivetrain losses. While this is only an estimate, it shows just how drastic of a difference low gearing makes and how that with a TacoBox, no matter how loaded down you are from on-board refrigerators, roof top tent, and recovery gear, when the TacoBox is engaged the amount of required throttle to get up and over obstacles is drastically reduced due to the tremendous increase of torque.
Finally, we can now state the new advantages your truck will have with the TacoBox:
Discover how a Marlin Crawler
can make your truck unstoppable!
Incredibly safe in downhill descents and drop-offs:A gear ratio greater than 1.00 is considered a gear reduction because the output speed is reduced by a factor equal to the ratio. For example, a 2.00:1 ratio will have an input shaft speed equal to twice that as it's output. While this is true for energy sent downstream from engine to tire, the opposite occurs in the upstream direction: That is the engine spins twice for every one revolution of the tire.
Consider what happens to the engine when a force acts against a tire. With a factory low range of about 40:1, for every tire revolution the engine must rotate 40 times. Now the gear ratio is providing resistance to motion through which is known as Engine Compression Braking. Imagine if you shut your engine off, shifted into first gear, jacked one tire off the ground, and tried turning it by hand. For you to rotate the tire manually by hand you must also overcome energy required to move each piston through its compression stroke. Using the same above example vehicle, consider this:
|Engine rotations per 30° tire rotation||1.4||3.7||6.7||17.2|
|No. Compression Strokes, 4cyl engine||5||14||26||68|
|No. Compression Strokes, 6cyl engine||8||22||40||103|
|No. Compression Strokes, 8cyl engine||11||29||53||137|
Think of it this way: Your truck can weigh nearly 5 times more than factory and yet will still descend down hills equally as safe as a factory truck, traction limited of course. Going downhill is EXTREMELY safe with a TacoBox which provides UNPARALLELED driver control. Please take a look at this video for an amazing downhill brake-less TacoBox demonstration!
2WD Low Range:The TacoBox also provides a new Low Range that can be used independently of your factory transfer case, meaning you can now have Low Range even while in 2WD! This is very useful if you are backing a boat down a ramp, moving a trailer around your yard, or repositioning your truck in a tight camp ground and don't want to hassle engaging 4WD. Also, on the trail you can make sharp corners without having the issue of the front end binding with the rear end due to sharp corner radii. The new ways you may manipulate your truck is very useful with cutting brakes and performing other slow and controlled maneuvers on the trail.
Extra Drive train Mount (optional):As mentioned, the TacoBox includes provisions for a 1979-1995 style Toyota 4cyl or 6cyl crossmember mount which may be used for additional drive train support! This is entirely optional but is a great feature that spreads the drivetrain torque helping prolong the lifespan of your engine mounts. For this, we offer a Heavy Duty 6cyl wide-style OEM Toyota mount here. Depending on application, exhaust modifications may be required. Click to view an example image of a HD OEM 6cyl mount installed.
Full List of Benefits:
In conclusion, here is a comprehensive list of benefits for both Automatic and Manual Transmission owners that you get from the Marlin Crawler TacoBox. Click the image for a larger view, and consider scrolling down to watch our many YouTube action videos below!
Proposition 65 Warning for California Consumers
WARNING: Products we sell can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.p65warnings.ca.gov.