Q: My truck has begun to make a really strange sound sometimes when I try to start it. The normal sound of the starter is replaced by a high pitched zinging sound, and the engine doesn’t start. If I try starting it several times, it usually catches and the engine starts. What’s up with this?

— Adam Heller

A: This is an easy one! It appears from your description that the drive, an internal component of the starter, is beginning to fail. The starter drive assembly, a renewable part within the starter, contains the starter’s pinion gear and a one-way clutch. When in operation, the pinion gear pushes forward to engage teeth on the engine’s flywheel or flex plate, providing a gear reduction in the neighborhood of 20 to 1. This means the starter spins at about 20 times the speed of the engine (about 200 rpm to 4000 rpm) while cranking. The one-way clutch within the drive allows the starter to drive the engine, but prevents the engine from driving the starter.

Why the clutch? If the starter didn’t disengage from the engine upon startup, either due to operator error or mechanical or electrical failure, the starter would be spun to perhaps 30,000 rpm or faster, resulting in a huge electrical nightmare and possibly an explosion. When driven, the starter becomes a generator providing a sizeable and unregulated power source; it could even come apart due to the very high rotational speed.

The starter drive’s one-way clutch is more specifically called an overrunning clutch. This device resembles a roller bearing with ramps that allow the rollers to freewheel in one direction but wedge in the other. Bicycles use an overrunning clutch in the rear hub to allow you to pedal when desired, regardless of bike speed. If an overrunning clutch becomes worn or mechanically sticky, it may slip when it’s supposed to drive. In the case of your starter, this results in a very fast or “unloaded” starter spin, as it’s not driving the engine. Subsequent starting attempts may be successful due to heat-up or jarring of the rollers, but not for long.

Depending on the starter, the drive may be serviceable — the cost is perhaps $30 — but renewing just this part may be penny-wise, pound-foolish as opposed to installing a remanufactured starter assembly. Other internal starter parts may also be nearing retirement, and you’d be paying for disassembly and reassembly time, in addition to the labor to replace any parts.

Remanufactured starters can be a little spooky in quality. I’d opt for a big-name brand or look for a local rebuilder with a good reputation among repair shops. They all come with a replacement warranty, but labor reimbursement is likely not provided.