Pickup & 4Runner Kits (1979-1995)

Pickup & 4Runner Kits (1979-1995)

4-cylinder Pickup & 4Runner Transfer Case Setups

Installing a dual transfer case into a 4-cyl equipped truck requires moving your existing t/case back approximately 6.5 inches. The additional "Crawl Box" is installed between your transmission and t/case. All 4-cyl gear driven t/cases are 21-spline except for the 1986-87 turbo, which is 23-spline. 2.28:1 or 4.70:1 gears can be used in any combination in the two t/cases. The most common choice is one set of 2.28:1 gears and one set of 4.70:1 gears, known as a Dual Ultimate™ Crawler. When building a transfer case for 4-cyl applications, the stock 21-spline input gear can be used. When building turbo, V6 & V8 applications, we highly recommend using a larger 23-spline input in the rear t/case. Otherwise, failure of a factory 21-spline input gear is certain. Floorboard and drive shaft modifications are required. The factory crossmember remains in its original position.

Looking for info on our 4.70:1 Low Range Gear Kits?
If so then click here!

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V6 Applications


We now have NEW 100% REDESIGNED MC08 Billet Adapters Kits IN STOCK!

This is the STRONGEST Dual Case Adapter we've ever made with many new features.

More info coming soon. Please call for details and ordering info at (559) 252-7295!

ALL NEW MC08 Adapter Design!

Dual Transfer Case Adapters

This is our new Xtreme Duty MC08-XD USA-made BILLET aluminum adapter kit. Nothing else on the market even comes close to the strength and reliability of this Dual Case Adapter Kit.

Kits Includes: Double row bearing adapter housing, oversized Chromoly billet main shaft, 158% stronger double row bearing pressed and installed, 54% stronger heavy duty cage roller bearing pressed, installed, and greased, Marlin Crawler Turtle Knob & key way for shift fork, Toyota transmission output seal, Toyota gasket and seal kit, and all required attaching JIS-grade hardware.

Click here to view all the details of our Xtreme Duty Technology.
Click here for install instructions.


Marlin Crawler Gear Drive Unit

Crawl Box Dual Crawler Kit

Dual transfer case reduction unit featuring 21 or 23-spline. Complete, ready to bolt-on, reduction unit featuring dual adapter. All necessary hardware included. Includes factory shifter assembly with a Marlin Crawler Turtle Shift Knob Unit installs between transmission and transfer case. Floorboard and drive shaft modifications are required. Fits 1979-1995 gear driven transfer cases. 4 & 5 Speed application only.


Top Shifting Marlin Crawler MC08 HD

Dual Ultimate Crawler

This is the ultimate setup for your rock crawler. Features our 4.70 gears in the rear case and an Extreme Duty MC07 dual adapter plate. This will enable your truck to have 20 forward and 4 reverse gear combinations. Fits 1979-1995 gear driven transfer case applications. Available for 4 & 5 speed applications only.

Please note: We are currently not offering red housings. All orders will be shipped with cleaned, sandblasted, and bare aluminum t/case housings.


Heavy Duty Transfer Case Output Shaft Kit
Below are some products that you may need during your transfer case modification.
We also offer transfer case products for...
HD Shift Spring

This shift spring is an optional upgrade part for your transfer case that provides a stronger engagement and a better overall shift feel. Additionally, by applying more pressure on the shift detent, this spring decreases the chance for an accidental or unintended gear shift.

If your transfer case is popping out of gear on the trail, then this heavy duty spring may help. Easy to install from the outside without disassembly. Use one spring for a crawl box, or two springs for a transfer case.

Requires a 6mm hex socket to install.


Low Profile Drain Plug

Low Profile Magnetic Drain Plug (with Aluminum Gasket). This drain plug comes with an aluminum gasket for use with aluminum housings (such as a transfer case).


Marlin Crawler RF1A Gasket and Seal Rebuild Kit

This is a full gasket and seal rebuild kit for all 1979-1995 gear drive transfer cases.

Includes our Heavy Duty EcoSeal rear output seal. All other parts are genuine Toyota gaskets and seals!


Transfer Case Interior Shift Boot

When installing a dual transfer case it's often necessary to add a second shifter boot to cover the hole in the floor from the additional shifter. This boot properly fits the factory t/case lever and will keep out mud, hot air and road noise. This genuine factory Toyota boot features a laser cut, 14 gauge steel base plate with 4 screws and will not crack or split like cheap imitations. Boot measures 6" X 6" with a diagonal bolt pattern distance of 6-5/8" and is 3.5" high. Genuine Toyota Parts.


Speedometer Cable

When installing a dual case Crawl Box into your truck, your transfer case will be moved back the distance of the Crawl Box, which is 6-1/2". Because your speedometer cable attaches to the tail housing of the transfer case, it must be lengthened in order for it to reach. Our 8" speedometer cable extension provides the necessary distance to reattach the cable properly without any binds or tight corners. This is a must for all 1984 and newer applications, and strongly recommended for 1979-83 applications.


Crossmember Mount, Locktup 4x4

Lower gearing increases the vehicle's torque output and also the load on your drivetrain components. Transfer case mounts are especially at risk since they undergo massive stress everyday. Add some assurance to your rig with Locktup 4x4's USA-made Heavy Duty transfer case mounts with long lasting USA-made urethane bushings. This heavy duty mount will not split apart and fail like high mileage stock mounts. Laser cut and CNC formed thick steel plates provide the best fit possible, while high quality welds keep everything together.

Fits all 1979-95 gear drive transfer cases and 1982-95 4 cylinder cross members. Fully compatible with dual case crossmembers with provisions for two mounts.


OEM Toyota Shift Handle

Brand new Genuine Toyota transfer case shift lever. Fits 4 and 5 speed transfer cases from 1979-1995. Includes new Genuine Toyota boot.


Marlin Crawler Total Spline Input Gear

Total Spline Input Gear

This is our exclusive Total Spline™ 23-spline 2.28:1 transfer case input gear, the strongest 23-spline input gear in the world, period. Full-length Spline Engagement addresses one of the weakest parts of your t/case and minimizes dual case coupler wear to combat strip-out. This will convert a 21-spline 1979-1995 4-cylinder transfer case to a 23-spline version so that the stronger 5spd R150F (3.0L V6) and R151F (2.4L Turbo I4) transmissions may be used. Fits any gear driven t/case 1979-1995. Factory 2.28:1 Gear Ratio. Chromoly steel.


Marlin Crawler RF1A Transfer Case Rebuild Kit

Here is a full rebuild kit for your Hilux Gear Drive RF1A Transfer Case. This kit includes high quality Toyota parts including KOYO and Nachi bearings. Kit includes 32 parts.