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Transfer of Power: 32 Ways to Re-Gear, Replace, or Restore the Heart of Your 4x4

Posted in How To: Transmission Drivetrain on August 6, 2018
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Photographers: Courtesy of Manufacturers

While lift kits, aggressive tires, beefy bumpers, and winches make our rigs into more capable machines, the transfer case is the heart of the 4x4 experience. Whether yours operates with the twist of a dial or the throw of a shift lever, it is the device that ultimately splits your engine’s power between the front and rear axles, thus separating it from other machines on the road. If you need to show your T-case some love, we’re here to help. From simple slip-yoke eliminator kits and shift levers all the way to rebuild kits and entire three-speed T-case swaps, let us be your tour guide into the heart of your 4x4—because without this wondrous box, your 4x4 would just be another pavement-bound commuter sedan.

Taco Two-Case

Case Files: One transfer case under your Toyota Tacoma is sometimes not enough, and Trail-Gear understands. This adapter kit gives you what you need to install a low-range crawl box in front of the transfer case on your ’95-’04 Toyota Tacoma. The kit is built with thick walls for increased strength and offers more oil flow for better cooling.
Info: trail-gear.com

Shift Lever Solution

Case Files: For anyone who wants to smooth out the shift pattern in their non-Rubicon TJ or LJ Wrangler, Steinjäger is here to help. The kit uses the stock shift lever, comes with powdercoated brackets, and is said to eliminate cable kinking.
Info: steinjager.com

Two-Wheel Low

Case Files: Steering around tight trails can be made easier by having only the rear wheels spinning in low-range. The TeraFlex kit pictured adds 2-Lo to the shift patterns of JK Wrangler Rubicon models, and kits are available for TJ and non-Rubicon Wranglers as well.
Info: teraflex.com

Big Iron Case

Case Files: If your rig is running Rockwell axles with tires taller than a middle-school-age kid, chances are you might be looking for a big transfer case to divide up that horsepower. Boyce Equipment knows all about big 4x4s and is here to help with everything from rebuilt NP205s to pneumatically shifted, cast-iron transfer cases fit for a monster truck. The 5-ton T-138 transfer case pictured is one of many heavy-duty T-cases available.
Info: boyceequipment.com

Colossal Case

Case Files: Behemoth Drivetrain CNC machines the Colossus case from 6061 aluminum, making it lighter and stronger than stock transfer case housings. The T-case can be clocked in multiple positions, comes with twin-stick shifter mechanisms, and is available for Dana 300 and NP205 applications.
Info: behemothdrivetrain.com

For the Four-Bangers

Case Files: Is the NP231 in your ’91-’01 Cherokee damaged beyond repair? Did your ’91-’02 TJ or YJ Wrangler come without a transfer case? Not to worry, Omix-ADA has direct-fit factory replacement units on hand.
Info: omix-ada.com

Vibration Reduction

Case Files: 4 Wheel Parts has a solution for shaky drivelines behind the NP231 transfer case. The store stocks Pro Comp’s Tail Shaft Conversion Kit, which shortens the driveline by 4 inches, making space for a CV shaft beneath your lifted 4x4.
Info: 4wheelparts.com

Brace Your Case

Case Files: The Transfer Case Brace from Rock-Slide Engineering keeps the transfer case under your ’07-’18 JK Wrangler safe from damage due to unexpected vibrations. The brace is said to bolt up without any need to remove driveshafts or the transfer case itself.
Info: rockslideengineering.com

Designed for Off-Road

Case Files: Whether you need repair parts for your NP205 or a completely overhauled trail-ready transfer case fitted with a Magnum Box for maximum gear reduction, Offroad Design is the place to look. The case pictured here is geardriven, bright orange, and ready to go under your off-road rig.
Info: offroaddesign.com

Ready for Rocks

Case Files: Skyjacker can help take your NP231 transfer case from regular to rock-ready by eliminating the old slip-yoke and replacing it with a fixed yoke, which is said to be tougher and ready for the abuse of wheeling.
Info: skyjacker.com

Born From Tractor Pulls

Case Files: With its beginnings in the tractor-pulling scene, SCS Gearbox now creates T-cases for many motorsports, including monster trucks and trail rigs. This two-speed planetary case is crafted from billet aluminum, is clockable to the left and right, and fits the needs of trail riders and racers alike.
Info: scsgearbox.com

Rugged Reduction

Case Files: Complement the lift and CV-style rear driveshaft on your ’87-’06 Jeep Wrangler with a Slip Yoke Eliminator Kit from Rugged Ridge. This kit comes with hardware, instructions, and everything you need to eliminate your failure-prone slip-yoke.
Info: ruggedridge.com

Black Box

Case Files: NorthWest FabWorks opened a Pandora’s box of gear reductions with the BlackBox. Adding the BlackBox to your powertrain gives you a higher final crawl ratio and an additional 2.72:1 low-range option, while still maintaining your rig’s 1:1 drive functionality. Variations of the BlackBox are available for the NP205, Dana 300, and other popular transfer cases.
Info: northwestfab.com

Prevent Pump Rub

Case Files: If your rig is a GM electronically shifted four-wheel drive from ’98 to ’07, chances are the T-case will experience “pump rub.” The replacement NP263XHD transfer case from Merchant Automotive will remedy this problem and also trap metal shavings with a magnetic drain plug.
Info: merchant-automotive.com

Tom Wood’s SYE

Case Files: The NP241C transfer case, pictured here, is a chain-driven aluminum T-case found under many common 4x4s and can be made stronger with a Slip Yoke Eliminator Kit from Tom Wood’s Custom Drive Shafts. This kit is said to fit many sizes of driveshafts, including those with 1310, 1330, 1350, and 1410 series joints.
Info: 4xshaft.com

Crawling Taco

Case Files: Give your Toyota Tacoma, 4Runner, FJ Cruiser, or T100 the super-smooth, slowed down, low-range crawling capability you’ve always dreamed of with Marlin Crawler’s TacoBox. This dual transfer case system gives you four crawling speeds to choose from, for the best traction no matter how loose, twisted, or tilted the terrain.
Info: marlincrawler.com

Replace a Case

Case Files: Did you damage your transfer case and need some new parts? Summit Racing stocks a rear half from USA Standard Gear that fits the NP249, NP261, NP246, and NP263HD T-cases.
Info: summitracing.com

CV-Ready

Case Files: RT Off-Road has a slip-yoke-solution for the NP231 T-case under your TJ or YJ Wrangler, ’87-’01 Cherokee, or ’87-’92 Comanche. The kit has a replacement output housing, new mainshaft, a CV-ready output yoke, and all necessary hardware for installation.
Info: rtoffroad.com

Remanufactured Wrangler Case

Case Files: RockAuto is the place to go for remanufactured transfer cases like this NP241 from Zumbrota. These T-cases have been cleaned, inspected, rebuilt, and tested—and are ready for use on- and off-road.
Info: rockauto.com

Rebuilt Monster

Case Files: Monster Transmission takes great care in rebuilding the NP246 T-cases found in Chevy and GM 4x4s. From bearings and seals all the way to the chain, each unit is rebuilt and tested before it finds its way beneath your rig.
Info: monstertransmission.com

Tranzilla

Case Files: Rockland Standard Gear has engineered a heavy-duty replacement for the NP246, NP261, NP263, and NP149 transfer case rear halves. In addition to being thicker than the OEM units, the Tranzilla HD case is said to eliminate a few costly fixes that tend to afflict longtime users of these T-cases.
Info: rsgear.com

Super Shorty

Case Files: When your rig is lifted above stock height, you need a kit that gives your rear driveshaft the clearance to keep spinning at full articulation. JB Conversions overbuilt this NP231 slip-yoke eliminator kit, pictured here, from the end yoke to the output shaft, giving you more engineering for your dollar and allowing for the most length in your rear driveline.
Info: jbconversions.com

The Atlas

Case Files: Advance Adapters builds the Atlas transfer case using 356-T6 aluminum alloy, helical-cut and synchro-equipped gears, and a twin-stick design for smooth shifting. Choose from an array of optional gear ratios anywhere from 1.5:1 to 5:1 to best suit your off-road needs.
Info: advanceadapters.com

Shortened D300

Case Files: Novak Conversions has all you need to shorten the output on your cast-iron ’80-’86 Dana 300 transfer case. The Novak 300RX includes a heavy-duty output that measures in 1.8 inches shorter than the traditional long-output version. The kit also includes a 32-spline alloy shaft, two tapered roller bearings, and a tailhousing cast from 356 aluminum.
Info: novak-adapt.com

Fixed Yoke, Reliable Yoke

Case Files: Driveline vibrations and lifted Jeeps go together like peas and guacamole—fix that with a Slip Yoke Eliminator Kit from G2 Axle & Gear. G2 provides the rear output yoke, output housing, mainshaft, and hardware; you provide the longer driveshaft.
Info: g2axle.com

Square Headlight Beef

Case Files: Quadratec carries the Atlas II T-case, which helps you add the 4.3:1 low-range gearing and lightweight aluminum strength you need for your ’87-’95 YJ Wrangler.
Info: quadratec.com

T-Case Drop

Case Files: Comanches and Cherokees lifted between 4.5 and 6.5 inches can suffer from driveline vibrations due to extreme driveshaft angles. Rough Country has an easy correction for this problem with the Transfer Case Drop Kit.
Info: roughcountry.com

Fabtech Fixed Yoke

Case Files: What goes perfectly with big tires and a lift kit? A trip to Fabtech’s website to check out the Fixed Yoke Kit for the NP231 transfer case.
Info: fabtechmotorsports.com

Saving the Day

Case Files: Boasting a variety of gearing options, wins at the King of the Hammers Ultra4 race, and massive internal gears, the Hero transfer case from Trail Worthy Fab is your go-to when you need a transfer case of heroic proportions.
Info: trailworthyfab.com

Designed for Adventure

Case Files: Say no to driveline vibrations in your ’97-’02 TJ Wrangler with the Nitro Slip-Yoke Eliminator Kit from Nitro Gear & Axle. Comes with all necessary hardware as well as an installation manual.
Info: nitro-gear.com

Bearings and Seals

Case Files: Motive Gear offers you the bearings and seals necessary to overhaul your BW1356 transfer case. This T-case is found under ’87-’96 Ford Broncos, ’89-’07 Chevy K3500s, ’87-’97 Ford F-150s, and other popular 4x4s.
Info: motivegear.com

Get Yoked

Case Files: An upgraded transfer case is no good if the yoke can’t get power to the driveshaft reliably. This 32-spline yoke from JE Reel Driveline is compatible with NP205 T-cases and fits a 1410 series U-joint.
Info: reeldriveline.com

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