Angle Gear & Transfer Case Terminology, Explanation

Angle Gear, Diff & Transfer Case

Angle gear = bevel gear = transfer case. Different names for the same 90 degree gearbox that bolts to the sideways oriented transmission and turns the power flow 90 degrees so the driveshaft points to the rear axle with the AWD control system on the front of rear differential.

The angle gear units do not have gear parts available from Volvo as spare parts. The bearings and seals are serviced but not the actual gears. One of the gears is mounted to a spindle using a specialized adhesive and is pressed on. The press fit makes that spindle not usable to properly retain a new gear pressed onto it.

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I talked to some local Volvo mechanics, the Volvo sleeve is basically unchanged from the factory one. Not sure why they don’t upgrade it.

• It always strips on the Angle Gear side, not on the Transmission side.
• It has an average lifespan of 80K-100K etc.
• So if you replace your sleeve, soon or later it will go out again. Not a big deal if you want to keep you car as FWD only.

After I looked at the stripped sleeve at the mechanic shop, I noticed the following:

• The Transmission side of the sleeve looks good, the Angle Gear side is rusted and stripped.
• The Right Shaft Axle passes right through the sleeve, through the smaller seal, into the Transmission itself.
• The Sleeve has its own seal (the larger seal).
• The Transmission side of the sleeve is bathed in ATF —> no rust.
• A thought from me: if you replace the sleeve —> good idea to grease it well on the Angle Gear side to prevent rust, and potentially another sleeve failure. In fact, the grease is included in the kit.

So, if people remove the Angle Gear to convert the car to FWD, they must keep the Sleeve in place, otherwise, ATF will leak out.

Some photos:

• If you buy the kit, you get small and large seals, grease, and 5 bolts (if you decide to reseal the Angle Gear 2 halves).

• Note the locations of small and large seals and their relationship to the sleeve and axle.

Angle Gear & Transfer Case Terminology, Explanation