Common questions about commercial vehicle transmissions

As the UK's leading supplier of replacement commercial vehicle transmissions parts, H L Smith have a wealth of information about parts and maintenance of your commercial vehicles.

If you have a problem you need to resolve, try our FAQs. PLease click on the links below for specific questions and answers.

If you can't find what you're looking for, please contact us and we'll get back to you as soon as we can.

Allison World Series automatic transmission

Addressing some common transmission problems e.g. no power to selector, problem engaging drive, and a "do no shift" light.

Axle carrier failure

Common symptoms and causes of axle carrier failure including differential spinout, shock failure and lack of lubrication.

Common gearbox faults

Does your gearbox jump out of gear? Here are some things you can check.

Drivehead problems

Investigating oil leaks, excessive noise, loss of drive and crabbing.

Electronic Control Units

ECU not working?

H L Smith's gearbox services

Gearboxes - general questions

Power Steering Faults

Power steering warranties, leaks and steering problems.

Propshaft Problems

Common causes of vibration and how to check for problems.