Correcting the Singling Hack Job

Improperly Singled

The only proper method of singling out a truck is to remove the mid axle, move the rear axle up, have a drive shaft made, and shim the rear axle to achieve proper driveline angles.

ANY THING SHORT OF THIS IS INCORRECT. DO NOT ACCEPT A TRUCK THAT LEAVES THE POWER DIVIDER AXLE IN PLACE !

DISCLAIMER: There are several folks who have been running power divider axles without problem. To them I say great, I'm glad it works for you. I prefer to do things properly. I'd also say, wait until you have a problem to swap it all out. This is heavy ugly work to do yourself, and silly expensive to pay someone else to do it.

The gentleman that I bought my truck from use to single them properly. This was in the early days of his business. Recently he has been leaving the middle axle in place and just chopping off the rear. This has several flaws, one potentially dangerous.

The mid axle was never designed to be a full time engaged drive axle. It has an air lock mechanism the engages it. If you lose air pressure, there is a mechanism to release the brakes to allow you to move the truck off the road. This will not work for you because there isn't any pressure to engage the rear axle. If you experience this failure, you are stranded in the road until you are towed away. Pray this doesn't happen in mile nine of an 18 mile construction zone with barriers on both sides.

The power diverter axle is a low speed axle designed to be run for short periods of time on questionable terrain to provide additional traction. It is not designed to be a primary traction axle. It is also not designed to be engaged over 60mph.

The yoke rotating in the back has nothing to connect to and because it's under load continuously, that seal will not last and will leak at fairly short service levels. It also is designed to pass torque back through the system while the engine brake is engaged. It is not designed to be the primary load system in an engine brake application.

Below is the long story on how this has been corrected. I first called my local Volvo dealer to get a quote from the dealership. The quote to remove and replace the power diverter axle with new/refurbished parts, make a driveshaft, and shim to proper driveline angles was $9500. This didn't include any troubleshooting on the ABS system.

Leak at Rear Yoke

Leaking Pinion Seal

Leak at Housing Cover

My power diverter axle was leaking from three different places. After talking with Volvo technical support (1-800-52-VOLVO), my local Volvo dealer, the mechanic at Doonan's, the mechanic at Alpine Construction, the owner of Port Deposit Salvage, and looking at the technical specifications from Spicer, I made the decision to proceed with a full axle replacement.

Rockwell RT20-145 Rear Housing

Axle Spindle and ABS Sensor

Front of Housing

Here's the start of my new rear end. Finding the parts is the hard part. There is a heavy truck salvage yard in Port Deposit, MD. They had a gear set (3.58), a housing, pictured, and a set of axles. All of the costs for this project are shown at the end.

Demolition Complete

Parking Brake Air Valve

High Low Shim

Pictured is the parking brake air valve. Also visible are three open air lines. These can be used for air hitch suspension and leveling features. All are switched at the dash. One was for the hitch jaws, one is for the power diverter, and one was for the sliding commercial hitch.

The last picture shows the high-low shim that was used to secure the power diverter axle. The yoke on the new rear end is about 8" lower relative to the yoke on the power diverter axle. The shim is about ~1/4" thicker on the high side. By turning the shim around 180 degrees, the new rear axle will point up toward the carrier bearing. I won't know until it is all assembled and back on the ground how close this comes to proper spec, but it will be a lot closer than just moving the rear axle up.

Him Management, Me Worker

Lifting the Rear Differential

Adverse Conditions

There is light at the end of the tunnel. Having a fork lift with a 6' fork really helps lift it into place...even in the pouring rain.

New Brake Drum

TheBelly of the Beast

Why on Earth am I smiling?

Costs for the repair include a full bearing change out. Stripping and painting the axle assembly. Replacing rear shock absorbers.

Rear Diff, Housing, Axles: $1470

Credit Power Diverter: -$420

*Driveshaft with U-Joints: $459

*U-Bolts: $37.48

*U-Bolt Nuts: $23.20

*Shocks: $123.82

*Grade 8 HW: $115

*Five Gallons Gear Oil: $64.95

*Inner Wheel Hub Bearings: $46

*Inner Wheel Hub Races: $29.98

*Outer Wheel Hub Bearings: $53.98

*Outer Wheel Hub Races: $35.98

*Hub Seals: $51.96

*Differential Breather Valve: $7.99

*Right Stuff Gasket Maker: $23.99

Machine Shop Pressing in races: $60

Mechanic providing final torque on U-Bolts, Wheels: $60

Lodging: $68 (Propane)

Mechanic: $315

Shop Fees: $FREE (Thank you Dave)

Total For Repair: $2626.33

*Indicates New Parts

Final Note: There were several tools that I didn't have. Between purchase, rent, and borrowing I spent $275 on tools. I also spent two tanks of gas in a borrowed car, and $30 on tolls over 5 days running around to get parts and the like.