Differential Cases
Is the case in your differential cracked, or are the bearings no longer tight on the bearing journals? The differential case is the part the ring gear bolts onto, and it houses the differential gears. This category is for you if you want to replace the case without buying a complete unit.
What a differential case does
The case is the rotating part in the centre of the differential. Power is transferred via the ring and pinion, the ring gear is bolted to the case, and inside sit the gears that let the wheels turn at different speeds in corners. Cracks, worn bearing journals or wear around the cross shaft can cause noise and play and, in the worst case, damage the rest of the differential and rear axle.
How to choose the right case
Cases from ARB are named by numbers, e.g. 201, 205/208 and 117/143/147. Check that the number matches the unit in your car before you order. In this category you will also find products from OMIX. Also look at:
- The spline count and diameter of the axle shafts, which must fit the case.
- The ring gear bolt pattern and the gear ratio the case is designed for.
- Bearing type and bearing journal dimensions.
- What is included – check the product description for the specific part number.
Installation and setup
A new case typically requires the bearing preload and the backlash between ring gear and pinion to be set again, and the gear contact pattern to be checked. New bearings, shims and bolts can be found in differential installation kits. If you don't have measuring equipment and setup experience, the work should be done by a workshop. Change the oil after installation and check it again after a short break-in period.
Frequently asked questions
Can I reuse the ring gear and bearings on a new differential case?
The ring gear can often be reused if it is undamaged and matches the case's bolt pattern. The bearings should normally be replaced with new ones, as they are easily damaged during removal, and new ring gear bolts are often recommended.
How do I know which ARB case I need?
Find the number in the documentation for your current unit or on the unit itself, and compare it with the number in the product name, e.g. 206 or 170/172/174/176. If you are in doubt, contact us with the details before you order.
What are the signs that the differential case needs replacing?
Typical signs can be clunking or play when switching between throttle and engine braking, noise in corners or metal shavings in the oil. The cause can also lie in the bearings or gears, so the parts should be inspected before you replace the case.