51, 52, 53

Drive Axle Lubrication

Fluid level plug is threaded into the drive axle housing or on the rear cover and the fluid is to be filled to the level of the plug

Dead Axle

Designed to carry the vehicles weight and come in a variety of shapes and sizes

Full-floating axle shaft

Does not carry any of the vehicle weight on either end of the shaft

Installing the Thrust Screw

Does not normally contact the crown wheel during operation. Instead, it runs with approximately 0.010" to 0.020" running clearance. Contact with the trust screw is made only when the crown gear flexes under heavy load

Tag Axles

Lift Axles that are located behind the drive axles

Pusher Axles

Lift Axles that are located in front of the drive or mine axles, on trucks and/ or trailers

Center Support Bearing

Mounted in a rubber support to allow flexibility as the driveline moves up and down

Lube Pattern too close to tooth root

Move pinion away from ring gear

Abuse Failures

Occur as a result of lack of driver training or caring

Fatigue Failures

Occur over a period of time. They occur gradually and progress until the component fails

Shock Load Failures

Occur when a component is momentarily overloaded to a level that surpasses the base strength of the material causing it to fail immediately. This failure leaves a relatively flat and uniformly rough surface at a the fracture area

Torsional Vibration

One source originates from the power impulses from the engine caused by the forces on the crankshaft during each power stroke. The other cause is from the u joint angles or phasing

Driveshaft Angle Cancelation

Operating angles at either end of a driveshaft must be equal to within one degree to obtain acceptable cancellation of the non-uniform velocity created by joint working angles

Lubrication of U joints

Packed with just enough lubricant to hold the rollers in places and stave off rusting. Must be fully lubricated after installation

Secondary Couple Vibrations

Passed through or coupled through the hanger bearing in a heavy duty driveshaft. They are then passed alone the entire length of the driveshaft

Down-Speeding

Running the engine at lower speeds than usual but still achieving the necessary road speeds

Maximum Driveshaft Play

Should be no more than 0.012" but measurable play exceeding 0.004 to 0.006 should be investigated and corrected

Torque spec on plus

Should not exceed 35ft-lbs

Specs for 1810

Tube Diameter - 4.5"x0.134" Maximum Shaft Length - 75" Maximum Shaft Torque - 12,200ft-lb Max Speed at 3.0 degree U Joint angle - 3,400rpm

Differential Gears

Allow for speed differences between the two axle shafts of the drive axle when turning. (Allow for wheels to turn at unequal speeds)

Lubricants for Drive Axles

75w-90 & 85w-140

Driveline Vibration Diagnostic

Accelerate the vehicle to a speed slightly faster than the one at which the vibrations is the worst. Then, depress the clutch and let the vehicle slow down through the speed where the vibration was the worst. By depressing the clutch, the engine and the clutch slow down to idle and the transmission input is removed. No change in the vibration indicates that the engine, clutch, and the transmission are not the cause, and the driveshaft could be the cause.

Installing U joints

According to most manufacturers procedures, all driveshaft attaching hardware-bolts, nuts, straps, and lock plates must be replaced after removing and should never be reused.

Differential Locks

Air operated and consist of a differential lock switch on the dashboard

Non-uniform Velocity

All driveshafts use U-joints have a natural tendency to vibrate because of this

Self-Steering Axles

Allows the wheels of the axle to automatically follow the curve of a turn. This prevents the tire scrubbing during the turn

Removable Carrier

Also known as a banjo housing because its shape resembles a banjo with two necks

Driveline Angularity

Angles at the universal joints. Should not need to be reset in the field. If any modifications are made to vehicles, such as shortening or lengthening the frame or adjusting vehicle ride height, it may be necessary to check and adjust angles.

Tandem and Tridem

Arrangements that must allow for differences in axle speeds between the drive axles

Heavy Duty Driveshaft Weights

Can weigh well over 100lbs and removing the attaching bolts before supporting the shaft can lead to personal injury and/or damage to the shaft.

Transverse Vibrations

Caused by an out-of-balance driveshaft or system and occur once per shaft revolution

Mack Cam and Wedge System

Drive system that allows the cam attached to the drive axle with less traction to overrun. This forces the wedges into the other cam and sends more torque to the drive axle with traction

Spinout in inter-axle differential

Even more detrimental in this type because it turns at a much higher speed

Combating Critical Speed Vibrations

Increasing the diameter of the shaft tube

Twisted Tubing

Is usually caused by excessive torque loading

Most common driveshaft

Spicer 10 series, 1710 and 1810. The 10 series have recently been replaced by Spicer Life Series SPL-140 through SPL-350HD

Metal of choice for driveshafts

Steel

Most common cause of out of phase yoke

Technician failing to mark the slip yoke position before removal

Fastening Driveshafts

The caps can be a press fit into the shaft yoke and be retained with snap rings or clips. Alternatively, the caps can be held in place with straps and bolts or U-bolts and nuts. Finally, the bearing caps themselves may have a machined flange that, in turn, bolts directly to the yoke

Can the semi-circular driveshaft caps and bolts be reused?

The caps can, the bolts must be replaced

Removing Driveshaft

The first step in removal of a universal joint is to always attach slings or hangers to support the shaft before removing the hardware

Variable Length of Driveshaft

The shaft must allow the shaft to change length as the suspension oscillates

Strength of Driveshaft

The shaft must be strong enough to withstand the maximum torque from the engine multiplied through the transmission gearing

Spalling and Galling

Transfer of metal from one surface to the other caused by excessive friction between them

Spec for Spicer 1760

Tube Diameter - 4.00"x0.134" Maximum Shaft Length - 70" Maximum Shaft Torque - 12,200ft-lb Max Speed at 3.0 degree U Joint angle - 4000rpm

Specs for Spicer 1710

Tube Diameter - 4.00"x0.134" Maximum Shaft Length - 70" Maximum Shaft Torque - 7700ft-lb Max Speed at 3.0 degree U Joint angle - 4000rpm

Phasing

Universal operating angles of this means that the output yoke of the joint doing the cancellation of the non-uniform velocity has to be doing exactly the opposite of the driven yoke of the input universal joint

Cause of U joint Fractures and Breakage

Usually caused by shock loads

Operating angles of U joints

should be kept as small as possible- preferably three degrees or less. An angle of 3 degrees can be expected to last 90% or more of its normal wear life

False Brinelling

Without lubrication, the needles start to dig into the trunnions. Which is the wearing away of the trunnion in the shape of the needles.

Inter-Axle Differential

Works in the same way as a drive axle differential

Can single drive axle differential lock be actuated while in motion?

Yes, provided no wheels are turning at different speeds or slipping