Manufacturer specifications apply. This page explains concepts only. Torque values, clearances, preload, backlash ranges and procedures vary by axle model and must come from the vehicle or component manufacturer's service information. This directory does not publish repair specifications.
What this service covers
Axle alignment is about where each axle points. On a solid rear axle or a truck tandem, the axle must be square to the vehicle's centerline; otherwise the vehicle tracks sideways (thrust angle) and tires scrub.
On heavy trucks, tandem axles must also be parallel to each other. Misalignment shows up as tire wear, steering pull and higher fuel use.
Common signs
- Vehicle 'dog-tracks' or the steering wheel is off-center when driving straight
- Rapid or uneven tire wear on the rear or drive axles
- Pull that a front alignment alone doesn't fix
What the work usually involves
- Measure thrust angle and, on trucks, axle parallelism with suitable alignment equipment
- Inspect suspension mounts, bushings and torque rods
- Adjust or correct using the vehicle's provisions (shims, adjustable rods, repositioning) within manufacturer limits
- Complete a front alignment referenced to the thrust line
Steps vary by vehicle and component design. Values and procedures come from the manufacturer's service information.
Vehicles this applies to
Cars and pickups with solid rear axles, vans, and medium- and heavy-duty trucks and trailers.
Key terms
Axle housing
The structural center section and tubes that enclose the differential and axle shafts and provide mounting points for suspension and brakes. A bent or cracked housing can cause misalignment, abnormal tire and bearing wear, and leaks.
Thrust angle
The direction the rear axle points compared to the vehicle's geometric centerline. A thrust angle that is out of specification can make the vehicle track sideways ('dog-track') and leave the steering wheel off-center.
Choosing a shop
- Confirm the shop works on your vehicle class and, for trucks, your axle make.
- Ask what parts they install (new, remanufactured or rebuilt) and what warranty applies.
- Check the listing's verification status and date in this directory.