Had a problem with my truck that I've never seen before with any vehicle, and I've owned them since the 70's.

I could tell the battery was weak this morning when I tried to start it, also knowing it's a couple months past its warranty life. (I don't know how they do it, but vehicle batteries now seem to last until the day the warranty expires.) Anyway, I hit the starter again and the engine started but the engine sounded like the pinion gear on the starter was slightly resting on the flywheel. I put in a new battery and heard the same noise though not as loud for about a half second and then it stopped. Haven't heard it since.

Why would a weak battery voltage cause the pinion gear to do that? Weak solenoid that may soon fail or something sometimes seen with a weak battery?

TIA

For what it's worth, I spoke with a neighbor who teaches Auto Mechanics at a local community college. He told me it's not too uncommon for a weak battery to be strong enough to engage the pinion gear and start the vehicle, but not strong enough to release the two. The pinion gear will then rattle against the fly wheel. He also mentioned it does not indicate a pending failure of the starter solenoid or pinion gear. Not exactly sure of this last one but I hope he's correct.

I have had weak/ poor battery and or connections which would throw starter gear to flywheel ring gear but would allow to slip engagement. A slow clicking sound. Seems to me it was GM products, but been while since owned aGM .

Seem to starter gear is on spring return. So, like you, I am sure of last statement.

But if the the clicking sound is rapid, my suspect would be a chipped ring gear on flywheel. A weak battery could agitate sympton.

Maybe this thread will get some traffic.

If it’s factory parts, the starter gear is a softer metal than the flywheel to allow it to be a failure point before the flywheel. So, to your point, could be a starter gear issue. The starter gears are also already chamfered so it doesn’t take much to shave them down a bit

But yes, it only takes a small percentage of the battery to actually start a vehicle. These gear reduction starters only need a quick blast of energy, not a sustained energy like the old ones with big external solenoids (which were also designed as a fail point).

As for it happening once with a new battery - it (starter gear) may not have retracted all the way with the weak battery and was “hanging” with the new battery on that first start. If you do hear it again, I’d say to drop the starter and inspect the gear

Question.. are the new gear reduction starters power disengaged? Could a weak battery cause the starter gear to remain engaged.

And.. So, gear with gear reduction motors, we no longer hear the slow click indication of a weak battery?

Thanks

The OP's original issue is not uncommon. Bendix springs fail all the time (see below). The mid 90's Northstar Cadillac engines has this issue and the bendix would rattle on right turns since the engine was in sideways.

Hardly any of the statements here are true ... especially the shop teachers'. The bendix (pinion) is mechanically returned home by a spring. This is not affected by battery voltage in the least. If the bendix is contacting the flexplate or flywheel, replace the starter.



Never heard of such.



See my first and second comment. There is a chance some numbskull engineer created an odd-ball starter and sold it to stockholders but I have never heard of a "power disengaged" starter.



Untrue. Low amperage causes the clicking. Voltage is like the speed of the electricity whereas amperage is the volume of electricity. Doesn't matter if gear reduction or not, permanent magnet or not, low battery reserve can cause the clicking. The solenoid not being able to stay engaged .... NOTHING involving the bendix to flexplate relationship...causes the clicking. So since the noise comes from the solenoid (which is a high AMP relay), the type of starter MOTOR matters not. Damaged teeth on the flexplate causes a grinding noise like a manual transmission with a broken synchronizer but only while the starter is turning the engine. I think what was mentioned was the clicking sound when the starter CANNOT turn the engine over.

Thanks for reply. Veryfied some of memory. Being blessed with means to change batteries prior to end of function, I havent had a battery failure in 20 years. But it is refreshing to learn old school rules still applies.

Appreciate the replies and added input.

The rattle has yet to return, at least for now.

The only starter issues I've seen are the proverbial "click" you hear when worn contacts or a weak solenoid keep juice from flowing to the starter motor. Yes, this can happen on a weak battery as well. But when you know for a fact the battery is good, it's a warning of pending hard fail. Thankfully, after a retry or two the contacts make up and the vehicle starts, still giving you notice of a pending hard fail.

The rattle that came with my issue was after the vehicle had started on a very weak battery.

Not for nothing but funny story - much younger me owned a '56 Cadillac with an electric 'eye' on the dash that was supposed to dim the headlights. Whenever the eye saw oncoming headlights it would turn off every light in the vehicle. I had to pull over, turn off the engine, and wait until the tubes (like old radios had) cooled off, then away I would go. When I made a hard right turn, the power seat would go up. Great fun...

Update: After several failures of the solenoid contacts resulting in the proverbial "click", I went ahead and replaced the starter with a new one. As I may have mentioned earlier, it was at least 100K miles ago that I replaced the solenoid contacts, and with the starter being original with just over 200K miles on it, I decided it was time. Besides, a hard fail during deer season is never a good thing.

Old battery with a worn-out starter; what could go wrong?

Did you put a new battery too??

Yes, did that first just to make sure the starter was telling me its death was imminent. It was a three-year battery that lasted 37 months. A good friend of mine told me he replaces vehicle batteries once the warranty expires. I always wait until they tell me their end time is close at hand. Throw a charge on them and get a few more miles out of them.