Atlas Transfer Case - F.A.Q

Frequently Asked Questions

Question: Why does my Atlas blow oil out the vent tube/breather?

Answer: Too much fluid will cause foaming at high speeds. Foaming oil expands and fills the entire cavity, which forces fluid out the tube; or the breather hose may be restrictive, causing the Atlas to build up pressure. On late model Jeeps, we have found that you must replace the restrictive breather (located on the firewall) with a free flowing atmospheric vent. This vent is typically found in earlier model vehicles. The stock vent was for lighter viscosity oils such as the ATF.

Question: Why does my Atlas pop out of gear?

Answer: Check for shift lever interference around the floor and dust boot. Make any additional clearance modifications needed. Engine and transmission mount combinations vary in rigidity, allowing some with more movement than others. The "TJ" support is by far the softest we have seen.

Question: How should the unit be flat-towed? And how is the unit oiled?

Answer: For flat-towing recommendations, please refer to the towing subheading in the Operating section of this manual. In reference to lubrication: The Atlas gears are supported on the shaft by a full complement of needle bearings. This design allows for less friction to develop in the unit. As long as the proper oil level is maintained while driving the vehicle, proper lubrication to these bearings is being achieved.

Question: Where is the .090" shim?

Answer: This question only relates to YJ customers. The .090" shim is the white washer that is included with the shift indicator plug. (The .090" washer is installed with the indictor plug on the Atlas shifter housing). The reason we use this shim is that Jeep used a couple of different shift indicator switches. To simplify our assembly and inventory, all of the Advance Adapters shift housings are machined alike. The .090" shim sets the proper height for your application. Refer to your instruction sheet provided with the Atlas transfer case.

Question: Does the Atlas have provisions for a P.T.O. unit?

Answer: No. We find very few P.T.O. units being used today. Therefore, the Atlas does not have provisions for a P.T.O. However, some transmission models do include this capability if you need this compatibility.

Question: My Atlas seems to be noisy and has a rattling that resonates up through the handles. What is the cause?

Answer: We have had a few customers that have complained of different noises. In every unit we've inspected, we still have not been able to find any type of problem with the Atlas itself. With our experience at this time, most noises originate with improper driveline angles. If you feel any vibration at the shift levers, your pinion angles need attention! Refer to the Final Installation section under the subheading Visual Inspection for driveline information.

Question: My Atlas seems to be hard to shift. Why?

Answer: It could be one of two reasons. First, the linkage could be binding. You may need to inspect for possible trouble areas. Refer to the Final Installation section under the subtitle Shifter Problem Checklist for more information. Second, the Atlas has shift rail detents, controlled with a ball and spring set. You can back off the brass set screws located on the shifter boss about a 1/4 turn, allowing an easier shift. As the unit is operated, components will seat in. After the first service, the brass set screws should be tightened 1/4 turn to return them to their original position.

Question: Can I change my Atlas gears to a higher or lower ratio?

Answer: This option is available; however, the parts & labor necessary may not be cost effective. New gears would be required. Items such as bearings, seals, and gaskets would need to be replaced. And shipping and labor costs would also apply. We can quote you on the cost of an upgrade, or the other recommendation we could offer is that you sell your current Atlas and purchase a new one with the desired ratio.

Question: How long has the Atlas been around and how many miles have you heard put on a unit?

Answer: The Atlas has been in production since 1996, so it has quite a number of proven years on the market. We’ve heard of several customers who have well over 100,000 miles on their units and still going strong.