Atlas 4 Speed Transfer Case Builder (#Atlas4)

Atlas 4 Speed Transfer Case

Advance Adapters has built upon the proven design of the Atlas 2, to create the revolutionary Atlas 4sp. No other transfer case on the market today has 3 separate low range ratios built into a single unit. This transfer case was designed for the off road enthusiast that likes to tackle a large variety of terrain with one vehicle. Selecting one low range ratio that works well for mud, sand and rock crawling, is a compromise but the Atlas 4sp overcomes this limitation. One transfer case that is perfectly suited to any terrain that you may want to conquer.

The 4SP has essentially two parts. The first is the reduction housing. This housing holds a planetary assembly that has a gear ratio of 2.72:1 when in “low” range, and a 1:1 in “high” range. It has one shifter coming out of the top to select the desired range. The planetary is not a synchronized shift-on-the-fly design and must be operated when the vehicle is stopped. (The main case still retains the shift-on-the-fly capability just like the standard Atlas). The reduction housing shifter is designed for a cable shifter.

The second part of the 4SP may look the same as the standard Atlas, but it does have some differences. The main case of the 4SP is the same raw casting, but has some machining variations to make it into a 4SP. The main case functions independently from the front reduction housing and retains all of the normal Atlas features (front and rear outputs controlled independently, and the “front only” option). All of the gears are the same. The front output uses all of the same parts along with the cluster. The strength of this unit is not an issue. We use a planetary assembly that was originally run in a NP241-HD transfer case. The six planetary gear setup has proven its durability and has been used in countless heavy-duty vehicles. Other attributes to the planetary assembly include a very quiet operation, easy shifting, and low rolling resistance. When all of this is put in front of a legendary Atlas Transfer Case, you get the best combination of gear ratios and reliability.

The 4SP units will fit nearly all applications that the standard Atlas will bolt to. These will include spline counts of 23, 27, 29, 31, 32 and 34. The unit has a circular bolt pattern on the front, identical to the one found in Jeep, Ford & Dodge vehicles. We have a variety of different adapters available to retrofit the 4SP into nearly any application. The twin sticks for the main unit can be either the standard linkage or the cable linkage. The standard linkage is offered in a variety of custom packages available for particular vehicles and can be modified to fit many custom applications. The installation of an Atlas 4 speed should be nearly the same as the standard Atlas 2 speed. The Atlas 4 speed is just a bit longer.

We do not recommend flat towing vehicles equipped with the 4 speed due to the additional bearings used in the planetary housing.

Since every Atlas transfer case is custom built to order, the unit will be customized to your vehicle. Please browse this site or give us a call to determine how to configure the ultimate transfer case, and have us build you one for your vehicle. CASE: Material: 356-T6 Heat Treated Aluminum Weight: 125 lbs. (dry) INTERNAL COMPONENTS: Gears: Helical Cut Planetary Gears: 6 Gears Helical Cut Bearings: Needle & Taper Rollers Synchronizers: Borg Warner Available Input Shaft Splines: 23, 27, 29, 31, 32, 34 Tail Shaft H.D., 32 Spline Front Output 32 Spline

RATIOS:

Low Range:1.5:1, 2.72:1, & 4.08:1 or

2.0:1, 2.72:1, & 5.44:1 or

2.72:1, 3.0:1, & 8:16:1 or

2.72:1, 3.8:1, & 10.34:1

High Range 1:1 LUBRICATION: Quarts: 2.5 Liters: 2.36 We are currently shipping Redline 75W-90 GL4 with all new Atlas units, this along with the other lubricants that are printed in our Atlas Installation Guide are the recommended fluids for the Atlas. LENGTH COMPARISON: *Atlas Short tailhousing is 16.75" *Atlas Long tailhousing is 18.75"

New Process 231 is 20.5"

New Process 241 Rock Trac T/C is 15-1/4"

Dana 300, 12"

Choosing a Gear Set:

Since there are numerous engine, transmission, and axle combinations, the need for various transfer case gearing options has increased. The 2 speed Atlas transfer case now has 6 different low gearing options to suit the needs of your driving habits and your drivetrain components. Along with the these different Atlas 2 speed ratio options, we are now producing our new 4 speed Atlas transfer case. The 4 speed Atlas gives you 3 low ranges & 1 high range - a few more choices when it comes to 4-wheeling. You can now have the ultra low gearing for rock crawling, a low range gear for trail use, and mid range for sand and mud. Whether you're looking at the 2 speed Atlas or the 4 speed Atlas, your ratio options will be diverse.

The wide variety of Atlas gear ratio options have been designed to accommodate any type of drivetrain combination. Please be aware that the lower the final drive ratio gets, the harder it is to stop the vehicle when in gear. Larger brakes will be required to slow the vehicle. Shifting the transmission into neutral on an automatic or depressing the clutch on a manual will be required to bring your vehicle to a complete stop.

Atlas 2 Speed Ratios

1.5:1 : This is a newer ratio that looks like it will be more popular for the 4 speed and used in quite a few competition rigs as a 2 speed.

2.0:1 : This unit is more of a stock ratio found in most early full size trucks and used in quite a few competition rigs

3.0:1 : This unit is popular in numerous applications. Used in quite a few competition rigs

3.8:1 : The Atlas 3.8 is a good choice for the avid 4-wheeler since this low gear ratio is ideal for moderate to some extreme rock crawling.

4.3:1 : This unit is popular in numerous applications.

5.0:1 : This unit is popular in numerous applications.

Atlas 4 Speed Ratios

1.0:1 / 2.72:1 / 1.50:1 / 4.08:1

1.0:1 / 2.72:1 / 2.00:1 / 5.44:1

1.0:1 / 2.72:1 / 3.00:1 / 8.16:1

1.0:1 / 2.72:1 / 3.80:1 / 10.34:1

With any of the Atlas ratios equipped in your 4WD, you have the opportunity to select a sensible ring and pinion gear ratio for great street performance. Combined with a low-geared crawl ratio of your choice, your vehicle will have the ultimate combination. This allows you to compete with the most well-equipped vehicle, but then be able to cruise comfortably down paved roads. If you are serious about on and offroad performance and dependability, then demand one of the Advance Adapters Atlas transfer cases.

All of the gear sets above except for the 4.3:1 and the 5.0:1 are available in two strength grades, “Original” & “Competition Ready”.

• Original: The tried and true Atlas gears that we have been producing for years. These gears will take plenty of punishment are perfect for everyday off road use and abuse.

• Competition Ready: These are for the hardcore off road enthusiast or competitor who wants and needs the very best, and tend to punish and push their equipment to the limits day in and day out.

1.Gear set Torque Capacity: 15%

2.Overall Gear set Life Expectancy: 300% (over Original Atlas Gear Set)

3.Overall Gear set efficiency: 2-5%

4.Cooler oil temperatures due to the increase in gear set efficiency

5.Reduction in gear noise: 3-5% (Shift Position: 4WD LOW. Input shaft speed: 4000RPM)

Choosing the Proper Input Shaft:

There are currently over 20 different Atlas input shafts in production today, varying in length and spline count. To completely understand your particular need when it comes to Atlas inputs first you have to look to the transmission that it will be mating to, and if any special adapters will be needed. Below is a list of the most popular transmissions currently being used today and the requirements for mating up to the Atlas. If your application is not listed below, it does not necessarily mean that we don’t have anything for you, it just may take a little more work to make it happen and will require call for further assistance.

Jeep Transmissions

GM Transmissions

Ford Transmissions

Dodge Transmissions

Choosing a Case Rotation:

When making the decision on what case rotation is best suited for you're vehicle there are a few things to consider:

• What side is your front differential on?

This will determine if you are in need of a passenger or a driver side drop case.

• What angle would you like the case to hang at?

In some cases the preference would be to have the case sit as close to level as possible, however in some applications this is just not possible due to clearances or interference issues. If a flat rotation is right for you, choose “*flat rotation”, keep in mind “*flat rotation” cases only provide a flat position and are void of any other clocking options.

If you are using a transmission that was originally coupled to a Jeep Dana 300 or a New Process Transfer Case having the standard 23 degree rotation (see photo below), the following rotation will be available when clocking the Atlas.

Atlas 2SP Left Drop 0, 18, 25, 32, 39, 46 Degrees

P/N ALC-T or P/N ALC-G2 (RACE CASE) P/N ALC-G2-FT (Flat Tow)

Atlas 2SP Right Drop 5, 12, 19, 26 Degrees

P/N ARC-T or P/N ARC-G2(RACE CASE) P/N ARC-G2-FT (Flat Tow)

Atlas 4SP Left Drop 0,17,24,31,38 Degrees

Atlas 4SP Right Drop 5,12, 19, 26 Degrees

If you are using a transmission that was originally coupled to a Jeep New Process having the factory 13 degree rotation,the following rotation will be available when clocking the Atlas.

Atlas 2SP Left Drop 0, 8, 15, 22, 29, 39 Degrees

P/N ALC-T or P/N ALC-G2 (RACE CASE) P/N ALC-G2-FT (Flat Tow)

Atlas 2SP Right Drop 0, 15, 22, 29, 36 Degrees

P/N ARC-T or P/N ARC-G2 (RACE CASE) P/N ARC-G2-FT (Flat Tow)

Atlas 4SP Left Drop 6, 13, 20, 27 Degrees

Atlas 4SP Right Drop 5, 15, 22, 29, 36 Degrees

When using one of our adapters to couple the Atlas to your transmission of choice you will in most cases have provisions for both 23 and 13 degree standard rotations. This opens up alot of potential clocking option for your install. (Note In some cases our adapter may only have one rotation) (see photo below),the following rotation will be available when clocking the Atlas using one of our adapters.

Atlas 2sp Left Drop 0, 8, 15, 18, 22, 25, 29, 32, 39, 46 Degrees

P/N ALC-T or P/N ALC-G2 (RACE CASE) P/N ALC-G2-FT (Flat Tow)

Atlas 2sp Right Drop 0, 5, 12, 15, 19, 22, 26, 29, 36 Degrees

P/N ARC-T or P/N ARC-G2 (RACE CASE) P/N ARC-G2-FT (Flat Tow)

Atlas 4sp Left Drop 0, 6, 13, 17, 20, 24, 27, 31, 38 Degrees

Atlas 4sp Right Drop 5, 12, 15, 19, 22, 26, 29, 36 Degrees

We have a few applications that GM did not offer an adapter or we do not make

an adapter housing for. These applications we offer the Atlas with a stock GM bolt

pattern option. Common transmission for this would be NV3550, Allison, & ZF.

Atlas 2SP Left Drop 7, 20, 27 Degrees Atlas 2sp Right Drop 0, 39, 46 Degrees

P/N ALC-T-GM or P/N ALC-G2-GM (GM RACE CASE P/N ALC-G2-GM-FT (Flat Tow)

P/N ARC-GM or P/N ARC-G2-GM (GM RACE CASE) P/N ARC-G2-GM-FT (Flat Tow)

Mechanical Speedometer Housing

The Atlas Standard 32 Spline tailhousing is the only housing that offers a speedometer option. The Atlas Standard 32 Spline tailhousing is designed to fit a stock Jeep (1982 & up) mechanical driven speedometer housing. These housings drive a cable that operates the speedometer. This speedometer housing is from a 1983 to 1986 Jeep CJ. The speedometer gear is not included with this housing, but by using the charts (Fig. E) that follow you can select the correct gear for your tire size and axle ratio. Some of these gears are hard to come by, so we may not offer the gear for your application. Note: The mechanical speedometer housing use the long style pinion gears. (pinion gears are not included with housing, however may be purchased separately) P/N300620

Plug The Speedometer Hole

If your application does not require any speedometer connections, we also offer a plug for the tailhousing to keep any dirt and debris out of the transfer case, and provide a sealed environment.

Electronic Style Speedometer Housing

The Atlas only accepts the mechanically driven YJ & TJ Speedometer. The late model Jeep TJs with the Rock Trac 241J transfer case used a tone ring and sensor for the speedometer pickup source. This combination is not able to be used on the Atlas tailhousing. The earlier NP231 style speedometer will work the same as the later model tone ring and sensor. One advantage is the mechanical unit is easy to modify when larger tires or different ring and pinions are used. The charts (Fig. E) that follow offer different drive gear part numbers to calibrate your speedometer. Note: The electronic speedometer housing use the short style pinion gears.(pinion gears are not included with housing, however may be purchased separately) P/N300637. Tire diameter is figured with the actual tire diameter not the size listed on the side wall. Most tires are smaller in diameter than the size printed on them.

Speedometer Calibration Chart

Ford Full-size truck & Bronco 87-91speedometers:

Regardless if your speedometer is mechanical or electronic, you must use our P/N 301506.

If you have a mechanical cable driven speedometer, a custom cable will need to be made. The 301506 has a 7/8" thread and the Ford is a metric thread. If your stock unit had a electronic set up, a cable adapter can be used from the 7/8" thread to a pulse generator that will send the computer the correct pulse needed. Both the mechanical and electronic components can be obtained from Nevada Speedometer 775-358-7422.

Toyota Speedometer Cable Adapter 1995-97:

This cable adapter allows the Atlas speedometer drive housing (P/N 301506) to couple to the stock Toyota speedometer cable. You can then retain the factory gauge and have all the added benefits of the Atlas transfer case. This cable adapter is sold under P/N 300613 and has a Toyota side- 22mm w/ .203 female fitting, and on the other end couples to the Atlas speedo housing side- SAE 7/8”-18 .104 square.

Toyota Speed Sensor 1998-Newer , FJ Cruisers, T100, Tacoma:

This kit allows you to retain the factory Toyota Vehicle Speed Sensor when installing an Atlas Transfer Case. A speedometer cable is used with a sensor housing to remote mount the VSS that was originally installed in the Toyota transfer case. This kit is sold under P/N 300605. You will also need the speedometer housing P/N 301506 for the Atlas and the proper drive gear.

With the Atlas transfer case being such a diverse case fitting into such a wide variety of vehicles, naturally we needed a variety of available transfer case yokes.

All of our yoke options are called out by their series number, and style.

Series Number

The series number is a classification that was standardized by the Spicer corporation that refers to the size of the yokes bearing width and cap diameter.

Yokes we offer are:

1310CV, 32 spline PNA1310CV

1330CV, 32 spline PNA1330CV

1350CV, 32 spline PNA1350CV

1310, 32 spline PNA1310

1350, 32 spline PNA1350

1410, 32 spline strap PNA1410

1410, 32 spline U-Bolt PNA1410U

1310/1330/1350 FLANGE YOKE, 32 spline PNAF1300

(1300 series Flange yoke is drilled and tapped for (4) 1/2"x 20 bolts on a 4.25"diameter,(4) 7/16"x 20 bolts on a 3.50"diameter and has a 2.0" male index for the mating yoke.)

Spicer companion yoke numbers are as follows:

(1310 C.V., P/N 211229x), (1310 non-C.V., P/N 2-2-939), (1330 C.V. - P/N 211631x), (1330 non-C.V., P/N 2-2-1369), (1350 C.V., P/N 212024x), (1350 non-C.V., P/N 3-2-1579).

1350,1410 FLANGE YOKE CV, 32 spline PNAF1350 ( Yoke has a 3.125" male index for the mating yoke.)

1350,1410 FLANGE YOKE non CV, 32 spline PNAF1410

(1410 Flange yoke is drilled and tapped for (4) 12mm x 1.25 bolts on a 3.75"diameter and has a 2.75" female index for the mating yoke.)

1410 non C.V. flange yoke. Spicer companion yoke number is 3-2-1329 (1410 non-C.V.)

1480FLANGE YOKE, 32 spline PNAF1480

TOYOTA FLANGE YOKE (3 BOLT PATTERNS 60mm x 60mm, 64mm x 56mm, & 68.3 x 60mm) PNAFTOY

Flange yoke may require the companion flange bolts to be installed through the yoke before the yoke is installed onto the transfer case. This depends on the series of companion yokes used. If the flange yoke is currently installed on your transfer case, you may be required to first loosen the yoke retaining nut, pull the yoke away from the transfer case enough to install the companion flange bolts. Once the bolts are in place, a new yoke lock nut should always be installed and torqued to 150 ft.-lbs. to secure the yoke to the transfer case.

Size Chart

Yoke Style

The two common yoke styles are CV (Constant Velocity) also referred to a "Double Cardan" and Non-CV. The CV style utilizes a carrier block (Cardan) that contains a set of two bearings, one per side. One side of the carrier (Cardan) is bolted to the transfer case output yoke, capturing a bearing between the transfer case output yoke and one side of the carrier, and the other bearing is captured between the other side of the carrier and the yoke affixed to the drive shaft. This type of yoke setup is most commonly used when attempting to overcome step or compound drive shaft angles.

The Non-CV style yoke uses only one bearing that is secured between the transfer case output yoke and the drive shaft yoke using straps or u-bolts.

Yoke Modifications: Changing the style of yokes on the Atlas transfer case may require your new yoke to be modified. When installed on an Atlas, the yoke will load up against a tapered roller bearing. Some yokes require a chamfer to be machined to clearance the cage of this bearing. All the yokes we offer have this chamfer.

Standard 32 Spline Atlas Tailhousing P/N ALT32 or Atlas Flat-tow options

The Atlas transfer case can be ordered with a standard rear tailhousing that accepts a stock Jeep speedometer from Jeep vehicles 1982 & newer (non flat tow). If a speedometer drive is needed, we offer the electronic version or the mechanical drive version. The speedometer provision on the Atlas also allows you to calibrate your speedometer for tire and gearing changes; and we do offer all the speedometer gear options. The Flat Tow tailhousing comes with or without a speed sensor for the Jeeps or GM's. This tailhousing is approximately the same length as the standard Atlas tailhousing PNAFT-JP for Jeep PNAFT-GM for GM and PNAFT-STD for no speed sensor.

Note:The standard Atlas transfer case comes with a rear tailhousing that accepts a stock Jeep speedometer from Jeep vehicles 1982 & newer. Atlas units ordered for earlier Jeeps or any other vehicle can use a mechanical drive speedometer housing PN301506. This housing is the same as 82-86 Jeep speedometer. To connect to this housing, a special cable fitting may be necessary. The speedometer provision on the Atlas also allows you to calibrate your speedometer for tire and gearing changes. We offer a full list of speedometer gears to do this, PN300620 fits the 82-86 housing and PN300637 fits the 1987 and newer housings. Note, the speedometer hole can also be plugged on this tailhousing by using PN300621.

Heavy Duty 32 Spline Tailhousing P/N ALT32HD

The HD Atlas rear tailhousing is basically the same as the standard housing with the exception on the output shaft. The output shaft in this tailhousing is manufactured out of 300M steel. This was introduced into our product line for a special aftermarket military vehicle. This high grade steel shaft is 130% stronger than our standard output. This kit is not necessary for most applications; however, for extreme horsepower and torque this Atlas HD tailhousing may be for you.

Short 32 Spline Tailhousing (No Speedometer) P/N AST32

Since rock crawling events have become steadily & increasingly popular, so have the requests for additional Atlas upgrades. The rock crawling industry has ventured into shorter drivetrains and light weight rear engines combinations. With these newer combinations, we were prompted to build a shorter Atlas tailhousing. This new tailhousing is 2” shorter than the standard Atlas tailhousing. It is designed for trail or competition use only since it does not provide provisions for any type of speedometer.

Short 32 Spline HD Tailhousing (No Speedometer) P/N AST32HD

The output shaft in this tailhousing is manufactured out of 300M steel. This was introduced into our product line for extreme competition grade applications. This high grade steel shaft is 130% stronger than our standard output, and is a must for any purpose built competition vehicle.

GM Electronic VSS Tailhousing P/N AVT32L and our HD kit is P/N AVT32LHD

Vehicle speed sensors (VSS) are mandatory for computer controlled engines and transmissions. The VSS sends information to the vehicle computer system for both engine and automatic transmission operations. Early Chevys up to 1992 used a computer that required a D.C. square wave input into the computer. These early computer system requirements could be fed by either a special speedometer drive or a reluctor ring. Chevys 1993 & newer required a A.C. sine wave. This sine wave creates a voltage that increases with vehicle speed. The only way that this voltage can be generated is through a reluctor ring mounted to either the transmission or transfer case shafts. This information was obtained from various sources, so please verify your requirements before doing any vehicle modifications.

Our tailhousing allows a sensor and reluctor to be installed in place of the speedometer drive. Our Atlas tailhousing had to have some slight pattern changes to incorporate this new feature. To add this option to an existing transfer case would require the purchase of a new tailhousing. This new option was primarily developed so that the Atlas could be installed into a newer Chevy 4WD vehicle. When ordering this tailhousing with an Atlas, we also include a standard shift control unit that is drilled and tapped to accept a low range switch. This allows the Chevy computer to re-calibrate the output shaft signal when in low range. Note: The Chevy computer may require some wiring and computer program changes for the different low ratios.

On Vehicles with computer controlled engine swaps, this tailhousing kit can provide the proper VSS signal when using a manual transmission. Vehicles with a computer controlled engine swap and an automatic transmission requiring a VSS should not use this tailhousing option unless a low range switch is installed and the computer program is modified. When installing this type of engine and automatic transmission combination, we highly recommend a reluctor ring location in the adapter or the transmission. This will give the engine computer system a correct 1-to-1 reading in or out of low range.