To determine if your axle shafts are candidates for cutting and resplining, they must meet two primary criteria:

1. The axle shaft must be the same size or larger than the original spline outer diameter (OD) at the point where the new cut is required. They cannot be smaller.
2. Typically, you must be removing at least 3 inches from the original axle to ensure the new splines are cut into fresh material past the original spline area.

Spline count must match your differential (carrier). If you are upgrading your differential, you should choose the spline count that matches the new unit. If you are replacing axles in an existing setup, you must count the splines on your current axle or identify the specific differential model to ensure compatibility. Power levels also come into play when upgrading to aftermarket axles. Feel free to call I to discuss where you need to be with axle spline sizes or carrier types.

No, a C-Clip axle is not considered race legal for most sanctioned competitive events. For racing applications, we recommend axle retention systems that do not rely on a C-clip like eliminators or press on bearing axles.

Yes, you can usually reuse stock drum brakes by following these requirements, as with all setups we do occasionally see exceptions so always call in and verify before starting:

• Use GM 10/12 Bolt Housing Ends designed for press-on bearings, such as the Moser 7900 housing ends.
• These are designed to work with a Big Ford axle bearing (3.150 OD).
• You must open the center hole on your backing plate to at least 3.200 OD so it can slide over the press-on bearing installed on the axle.

Press-on Bearings: These use an interference fit and a press ring to grip the axle. They typically require a 16–20-ton press for installation. The press fit is strong enough that side loads will not cause the axle to lose its seat.

C-clip Axle Bearings: These do not hold the axle in the housing. The C-clip at the splined end handles retention inside of the carrier. The bearing simply rides on the shaft and plays no part in retention.

C-clip Eliminators: These require modifying a stock C-clip housing or using aftermarket c-clip ends modified here in house. A press-on style bearing housed in a billet aluminum block is pressed onto the axle using a 16–20-ton press. The eliminator block is then bolted to the modified housing end to secure the axle.

Moser Engineering does not recommend C-Clip Eliminators for street use. They are designed specifically for drag racing (straight-line performance). In street applications, the aluminum block can flex during cornering or turning, which eventually leads to rear-end fluid leaks.

To have a housing narrowed, you must send the housing to us completely disassembled (clean and bare). This means no internal parts, brakes, or axles. You must include detailed instructions on the desired width, a return address, and a daytime phone number. Disassembled housings can typically be shipped via UPS when packaged or boxed correctly.

Your choice of fluid depends on the carrier or differential you are using. Moser Engineering manufactured items (axles, bearings, cases, spools) are compatible with any high-quality mineral or synthetic oil with a GL-5 or higher rating. However, specific differential manufacturers have different requirements:

• Auburn: Use high-quality non-synthetic 80W90 GL-5 gear oil with friction additive.
• Detroit Locker: Use petroleum/mineral-based oil. Synthetic is not recommended.
• Eaton Posi: Use GL-4 or higher mineral/petroleum-based oil with friction additive.
• Truetrac: Use high-quality petroleum/mineral-based oil. Synthetic is not recommended.
• Wavetrac: Use factory-recommended oil or high-performance equivalents. Do not use friction modifiers, limited-slip additives, or “Shockproof” oils, as these can reduce the friction necessary for the gears to function.

Auburn info.
What kind of oil and additive should be used with an Auburn Performance Differential?

It is important when installing an Auburn High Performance, Pro Series or ECTED® LOCKER that a high quality non-synthetic 80W90 GL-5 gear oil
be used. Treat the oil with Auburn Gear, GM or Ford friction additive. Three ounces of additive treats one quart of oil.
Friction additive part numbers:
Auburn Gear: 504102
GM: 1052358
Ford: C8A219B546A

Detroit Locker info.
What kind of oil should I use? Can I use synthetic? Do I need friction additive/modifier?

A quality petroleum/mineral based oil works best in the Detroit Locker units. We do not recommend synthetic oil. Friction additive/modifier is not required.

Eaton Posi info.
What kind of oil should I use? Can I use synthetics? Do I need a friction additive/modifier?

Eaton Posi units perform best when using GL4 (or better) mineral/petroleum based gear oil. A four ounce bottle of friction additive/modifier is also necessary for optimum performance.

Truetrac info.
What kind of oil should I use? Can I use synthetic? Do I need friction additive/modifier?

A quality petroleum/mineral based oil works best in the Truetrac units. We do not recommend synthetic oil. Friction additive/modifier is not required.

WAVETRAC® info.
WAVETRAC® GEAR OIL RECOMMENDATIONS

Your new Wavetrac® differential is incredibly durable and will withstand the harshest environments… as long as suitable oil is used.
Many customers ask what oil we recommend for use with the Wavetrac® differential.
We feel the best answer is:
Use the “factory fill.”

In other words, use the gear oil spec that your car manufacturer recommends for your car. The Wavetrac® is compatible with virtually all factory-installed gear oils used today.

If you are racing your vehicle, and wish to upgrade the gear oil to improve performance or durability in racing conditions, choose the oil carefully: be aware that some gear oils have additives that are not recommended for use with your Wavetrac®.

Some have friction modifiers designed for limited slip differentials. These modifiers generally increase slipperiness and are intended to reduce clutch disc chatter in conventional clutch-type LSDs.

Some gear oils such as Red Line Oil’s Shockproof® type have microscopic solid particles in immersion in order to “cushion” transmission components, acting as an extreme pressure agent.

The Wavetrac®, and all helical gear differentials in general, operate using friction. The friction generated between its internal gears and its housing are what allow this type of differential to function.

Gear oil additives that drastically reduce friction will actually reduce the performance of gear differentials. The internals of the diff get too slick to generate adequate friction – reducing the differential’s effectiveness – reducing its ability to drive both wheels.

In conclusion, when using a Wavetrac®:

• Use factory spec oils for your car
• Use factory-compatible high performance oils if you wish to upgrade the oil.

Please consult Autotech Driveline for recommendations.

• Do NOT use gear oils with friction modifiers or limited slip additives.
• Do NOT use Shockproof®1 or similar gear oils designed to reduce friction.

Please note that you will void the Wavetrac® Limited Lifetime Warranty if incorrect
gear oil is used.

1 Red Line Oil offers many, high quality, high performance gear oils that are compatible with Wavetrac® differentials. Only the Shockproof® types should not be used with the Wavetrac®.

We accept major credit cards including Visa, Mastercard, American Express, and Discover. We also offer additional secure payment options such as installment payments via credit partners as listed during the checkout process on our website.

Once your order has shipped, you will receive a confirmation email containing a tracking number. You can also log into your account on the Moser Engineering website to view your order history and current shipping status.

Yes, we ship our high-performance components worldwide. Shipping costs and delivery times vary based on the destination and the weight of the items. Please contact us directly for an accurate international shipping quote.

Moser Engineering is known for the fastest turnaround in the industry. While lead times can vary based on seasonal demand and specific requirements, most custom axle orders are processed and shipped within two business days.

Because we pride ourselves on fast processing, orders for in-stock items or custom-machined parts move into production very quickly. If you need to change or cancel an order, please contact us via phone immediately. Once custom machining has begun, orders cannot be changed or cancelled without incurring a base material core charge.

If your package arrives damaged, please document the damage with photos and contact the carrier immediately to file a claim. Once you have notified the carrier, contact Moser Engineering customer service so we can assist you with the resolution process.

Yes. We provide technical documentation on our website, and our staff is available to answer technical questions regarding the installation and fitment of our products. We recommend that all driveline components be installed by a qualified professional.

Moser Engineering stands behind the quality of our products. Warranty terms vary depending on the specific product (e.g., our specialized alloy axles vs. racing spools). Please refer to our warranty page for detailed information regarding coverage and limitations.

We offer both. Whether you need a complete rear-end assembly, a pair of custom axles, or just a specific bearing or shim kit, you can purchase individual components directly through our online store.