Parts for your 2018 Mazda 3-Universal joints

2018 Mazda 3 universal joints — what’s actually fitted

For the 2018 Mazda 3 (BM/BN series), universal joints (Cardan U‑joints) are not used in the driveline. Mazda’s factory Workshop Manual for BM/BN models (2014–2018) lists the front drive shafts as using constant‑velocity joints only: outer Rzeppa‑type CV joints and inner tripod/double‑offset (DOJ) CV joints, with no propeller shaft in this front‑wheel‑drive layout. Haynes’ Mazda 3 (2014–2018) service guide aligns with this, and standard driveline references (e.g., Bosch Automotive Handbook, GKN driveline design notes) explain that FWD cars require CV joints to transmit torque at larger steering angles while keeping rotational speed constant — something a simple U‑joint can’t do without inducing speed fluctuation and vibration.

That’s why a traditional universal joint isn’t relevant on the 2018 Mazda 3’s axles. U‑joints suit rear‑wheel drive or AWD prop shafts where joint angles are modest and packaging is straight, the Mazda 3 is front‑drive, with short half‑shafts that must handle big steering angles smoothly. CV joints deliver constant velocity through those angles, preventing shudder and torque ripple that a U‑joint would introduce.

There is, however, a small exception: the steering intermediate shaft typically uses a compact universal joint coupler to handle column angle changes. It’s not the “universal joint” people usually mean when talking axles, and it isn’t a routine service item — it’s replaced only if it becomes notchy, seized, or develops play.

• Driveline joints on 2018 Mazda 3: CV joints (outer Rzeppa, inner tripod/DOJ) — sealed, greased for life.
• Where a U‑joint might exist: the steering column coupler — inspected if there’s stiffness or free play.

For regular servicing, attention should be on the CV boots. At each service interval (or about every 10,000–15,000 kilometres), check for split boots or thrown grease and fix promptly to avoid CV joint wear. If there’s clicking on full lock, vibration on acceleration, or grease around a front wheel, book a CV inspection. If the steering feels tight or notchy around centre, have a technician assess the steering shaft U‑joint.

Popular questions about 2018 Mazda 3 universal joints

Does a 2018 Mazda 3 have universal joints?
No universal joints are used on the front drive shafts. The BM/BN Mazda 3 is front‑wheel drive and uses constant‑velocity joints on both half‑shafts. A small universal joint typically exists on the steering intermediate shaft, but it’s not part of routine driveline servicing.

What joints are on the front axles, and do they need regular maintenance?
The front axles use sealed CV joints. They don’t require periodic regreasing, just inspect the rubber boots during regular services. Replace any damaged boot quickly to prevent grit ingress and expensive joint wear.

What symptoms might feel like a bad U‑joint on a Mazda 3?
Clicking while turning points to an outer CV joint, and shudder on take‑off can suggest inner CV wear. Heavy or notchy steering can be a sign of a worn steering intermediate shaft joint. Any of these should prompt a proper workshop check.