Marlin Crawler Dual Ultimate Crawler
Why it's cool: The Marlin Crawler has evolved over the years, and today it's a household name among Toyota fans. We like the Dual Ultimate Crawler because it mates the super-tough MC07 dual adapter plate to a rear 'case with 4.70:1 gears. This setup offers 20 forward and four reverse gear combinations. The Ultimate Crawler fits '79-'95 geardriven transfer case applications with the four- and five-speed transmission. It is also available with 4.0:1 or 4.97:1 gears in either 21- or 23-spline configurations. It's worth noting that the MC07 adapter features a 5209W double-row maximum-capacity 32-ball bearing, cage roller bearing, oversized billet mainshaft, a new bearing retention system, and increased oiling capacity. In other words, it's tough.
How you can get one: You can get this setup directly from Marlin Crawler in Fresno, California.
NP241HD
Why it's cool: The standard NP241 was a good, but not great, transfer case. They were typically used in '87-and-up Jeep, Dodge, and Chevrolet V-8 applications. They use 2.72:1 planetary reduction gears for low-range and chaindrive for the front output. Typically they use a slip-yoke rear output shaft. We like the beefier NP241HD found in Dodge 3/4- and 1-ton trucks with the V-10 or Cummins diesel engines. Some of its upgraded features include a stronger front output chain that is 1/4 inch wider than the non-HD chain and a more durable six-pinion planetary instead of the non-HD three-pinion planetary.
How you can get one: This is a hard transfer case to find, but when we spoke with the folks at High Gear Transmission in Memphis, they had a unit in stock. If you already have an NP241HD, the team at 4xHeaven can get you parts or they can rebuild it for you in-house.
Lovell 357
Why it's cool: If you're into rockcrawling or rock racing, there's a good chance you've heard about the Lovell 357. If not, we'll tell you about it, because this thing is super trick. First off, the "357" moniker refers to its reduction ratio of 3.57:1. This single-speed, geardriven unit was designed for competition and features a premium-grade aluminum alloy housing and high-strength steel gears and shafts rated to withstand loads in excess of 11,000 lb-ft of torque. It weighs 115 pounds, is 9.22 inches in length, 18.23 inches in width, and has a height of 9.98 inches. It offers 32-spline output shafts and your choice of 23-, 27-, or 32-spline input shafts. Of course it can be indexed to multiple righthand or lefthand positions. The 357's most unique feature is that it uses pneumatic pressure to actuate clutches for the front and rear outputs. This allows instant engagement and disengagement under any conditions, without gear binding, via toggle switches. A small 68ci compressed air tank will cycle the 'case 500 to 1,000 times, and it can be engaged at virtually any rpm. The unit is also a direct bolt-in replacement for the Atlas II.
How you can get one: The 357 can be ordered directly from Lovell Engineering.
T-136-27
Why it's cool: This case was originally found under 2.5-ton military 6x6s. It's a monster unit that weighs approximately 400 pounds. The housing is cast iron and it's geardriven. It sports a 1.98:1 low-range ratio and is a divorced unit. Shifting is via air, and the experts at Boyce Equipment tell us that it only requires 36 psi. Over the years, this case was adopted by some monster-truck drivers looking for a unit that would hold up to the abuse of 66-inch tires. Even today, those with rigs running 2.5-ton Rockwells have found the T-136-27 to be the hot ticket for durability. It's important to note that there was an earlier version of the unit that was very similar visually. It was simply referred to as the T-136. This unit is not desirable because it has mechanical shift and an undependable front drive sprag.
How you can get one: Contact Boyce Equipment in Utah.