Standard Atlas Tailhousing
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 other vehicles can order a mechanical drive speedometer housing. This housing is the same as an early style Jeep. 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. This Atlas tailhousing is P/N ALT-T. If a speedometer is not needed, the speedometer access hole can be plugged by using PN300621.
Atlas Short Tailhousing (No Speedometer)
The rock crawling & racing industry drove the demand for the creation of the short tailhousing. We had inquires for new drivetrain combinations, shorter drivetrains and light weight rear engines combinations. With these newer combinations, we were prompted to build a shorter Atlas tailhousing. This 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. This new tailhousing can be retrofitted to any Atlas case by ordering PN301499R. If you’re ordering a new case, this item can be included on a new Atlas by using P/N AST-T. Not recommended for street use.
HD Atlas Tailhousings with 300M Output Shaft
The HD Atlas rear tailhousing is basically the same as the standard and short housing with the exception on the output shaft. The output shafts in these tailhousings are manufactured out of 300M steel. This was introduced into our product line for a special aftermarket military vehicle but also used in many of the performance racing applications. 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. The HD tailhousing is available for the all Atlas transfer cases at an additional cost, Part No. ALT-G2 or AST-G2.
GM VSS Tailhousing (No Speedometer)
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.
The VSS tailhousing kit we offer is P/N AVT-T
The VSS tailhousing kit for the 300M is P/N AVT-G2
If you have installed a newer GM engine into a Jeep with a manual transmission, you may want to retain the Jeep speedometer, but the GM engine needs the 40 pulse reluctor to function correctly. The standard Atlas transfer case tailhousing should be retained and one of our TruPulse kits should be used. These TruPulse reluctor kits fit on all of our Atlas tailhousings. These kits are an externally mounted unit that provides the True 40 Pulse required for the computer system. The reluctor ring gets mounted to the transfer case yoke. The kit is offered in several yoke styles. Note: These kits will not work with a flange yoke.
PN50-5040 with a 1310 non C.V.
PN50-5041 with a 1310 C.V.
PN50-5042 with a 1350 non C.V.
PN50-5043 with a 1410 non C.V.
Flat Tow Tailhousing
Introduced in 2018 the flat tow option was released for the Atlas transfer case. This new option uses a new rear output shaft that is connected to a gerotor pump assyembly. The Atlas pan has a pick up screen that pulls oil from the main case pulling it into the tailhousing and down the output shaft lubricating the bearings while driving and being flat towed. The length of the tailhousing is the same as the standard Atlas. It does not have the mechanical speedometer gear but offers an electronic pick up for a Jeep , GM, or STD which has no pick up.
P/N AFT-JP Flat Tow tailhousing with Jeep sensor
P/N AFT-GM Flat Tow tailhousing with GM sensor
P/N AFT-STD Flat Tow tailhousing witout a speed sensor